The best answer is B.
Carbohydrates, also known as saccharides , are molecular compounds made from only three elements namely carbon, hydrogen and oxygen.
They are also known as sugars. Some of these sugars are simple molecules called monosaccharides, such glucose made from just one molecule. Other carbohydrate molecules are very large, such as starch.
Starch is made up of a large number of monosaccharides namely glucose. Plants use starch as a way to store glucose and also as food in some mitochondrial processes.