The correct option is B Sieving
With the help of a Sieve, we can seperate two solids from each other which have different shapes. A good example for this is seperation of flour from grains.
Winnowing is the process of seperating lighter substance from heavier substance by using height and wind.
Filtration is the process mostly used to seperate liquids from solids.
Threshing is the process of loosening the edible part of grain from the straw to which it is attached.