Answer: Option A. "Vegetables"
Step-by-step explanation:
Carbohydrates are the biomolecules that act as primary source of energy. When body requires instant energy the biomolecule that is first consumed is carbohydrate.
Vegetables are the rich source of carbohydrate for example Potatoes, sweet-potato, corn and Beetroots.
Hence, among the given examples, Vegetables are the major source of carbohydrates.