We can separate salt from water by the method of evaporation. On heating the mixture, water evaporates and salt will be left behind.

Threshing is used for separating seeds from the harvested stalks.

Pebbles are bigger in size as compared to sand particles. Thus pebbles can be easily separated from sand particles by using handpicking.

• To separate solids that are insoluble in liquids and the solid is heavier than the liquid, sedimentation and decantation method is most suited. By leaving the mixture undisturbed for a long time, the larger and heavier solid particles settle down leaving the clear liquid above it. Once the solid has completely settled down, the clear liquid above is poured out leaving behind the insoluble heavy solid particles (decantation). 
• Evaporation cannot be suggested as a method of separation here because it is not mentioned whether the liquid or the solid is volatile or not.
• Filtration is not necessary as the solid particles are heavier and will automatically settle. If the solid particles were not heavy and will not settle down easily, we could have opted for filtration method.
• Condensation and crystallisation method is also not suited because we do not know from the question whether the solid is crystallisable or not.

Winnowing is used to separate heavier and lighter components of a mixture by wind or by blowing air.

The solution in which no more amount of solute can be dissolved at a particular temperature is called a saturated solution. On the other hand, an unsaturated solution is one in which more solute can be dissolved at a particular temperature.

Solution which contains maximum possible amount of solute at any given temperature is called a saturated solution. At any particular temperature, a solution that has dissolved as much solute as it is capable of dissolving is said to be a saturated solution.

On drying the water consisting of H2O molecules will evaporate and dry up leaving Sodium Chloride behind.

If the amount of solute contained in a solution is less than the saturation level, it is called an unsaturated solution. It can dissolve more solute in it. 

No, we cannot separate powdered salt and sugar by winnowing beacuse they are forming homogeneous solution.

 Sieving allows the fine flour particles to pass through the holes of the sieve while the bigger impurities remain in the sieve.

Option (C) represents correct statements.
Threshing is the process that is used to separate the grain from stalks. In threshing, the stalks are beaten to free the grain seeds.
Winnowing is the process used to separate heavier and lighter components of a mixture by wind or by blowing air.

Handpicking, winnowing, sieving, sedimentation, decantation and filtration are some of the methods of separating substances from their mixtures. 

Mixtures having more than two components can be separated by using more than one method of separation. For example, a mixture of salt and sand can be separated by sedimentation, then filtration and then evaporation.

When a saturated solution is heated, it becomes unsaturated, because it causes an increase in kinetic energy which leads to an increase in distance between the molecules of the liquid. So that the solute particles take free space present in the solvent. 

That is why saturated solution becomes unsaturated on heating.

Hence, option $$(B)$$ is the correct answer.

All the water gets evaporated but this is not suitable for the extraction of sugar. Crystals as the sugar crystals gets charged by heating it in this way. 

Wind winnowing is a method developed for separating grains from chaff. It is also used to remove weevils or other pests from stored grains. 

In its simplest form, it involves throwing the mixture into the air so that the wind blows away the lighter chaff, while the heavier grains fall back down for recovery. This includes techniques like using a winnowing fan (a shaped basket shaken to raise the chaff) or using a tool (a winnowing fork or shovel) on a pile of harvested grain.

A saturated solution of salt on heating becomes unsaturated solution. On increasing the temperature, larger quantity of salt can be dissolved in water.

Crystallization can be used for separation of a salt from its solution. Crystallisation is a separation technique that is used to separate a solid that has dissolved in a liquid and made a solution. The solution is warmed in an open container, allowing the solvent to evaporate, leaving a saturated solution.

A saturated solution is the one which cannot dissolve more of the solute at a given temperature. This is the point of maximum concentration, and the saturation point depends on the temperature and pressure of the solution.

Sugar syrup is a saturated solution of sugar.

From sugar syrup, solid sugar separates out as solid cooling and syrup become hard indicating that syrup is a saturated solution.

A mixture of glucose water can be separated by the method of evaporation. Water being a volatile substance will evaporate and glucose will be left behind. 

Seawater is trapped in large, shallow pools and allowed to stand there. The sun’s heat evaporates the water slowly, and common salt is left behind. This salt is further collected, purified, and packed for domestic use. The concentrated brine precipitates the salt, which is then gathered by mechanical harvesting machines. Any impurities that may be present in the brine are drained off and discarded before harvesting.

Bullocks are used for threshing. Threshing is the process which is used to separate grain seeds from stalk.

The method of separation of particles from a mixture based on the difference in size of particles is known as sieving. It uses sieve plates for separation of coarse particles from finer particles. Wheat flour is separated from wheat bran by the method of sieving.