Carbohydrates are used by body mainly:
A. For obtaining vitamins
B. As a source of energy
C. For building muscles
D. For all its development needs

Hint: Carbohydrates are generally known as the energy provider for our body like the food we take is also known as carbohydrates which are essential for our body. The main carbohydrates known by us are sugars, fibers and starch.

Complete answer:
Carbohydrates are found in grains, vegetables, fruits, milk and in other dairy products. These are basic food items but play an important role for our healthy life. The food which contains carbohydrates are converted into glucose or blood sugar during the digestion process. During the digestive system our body utilizes the sugar as a source of energy for cells, tissues and organs and the extra amount of energy is stored in our muscles.
The term carbohydrate is derived from the French word known as ‘Hydrate de carbone’ which means hydrate of carbon so we can say that carbohydrates comprises carbon, hydrogen and oxygen. The general formula of carbohydrates can be represented as ${{C}_{n}}{{({{H}_{2}}O)}_{n}}$. These can also be known by some other names like starch, simple sugars etc.
The main function of carbohydrates in our body is to provide energy and food to the nervous system. It is also involved in fat metabolism which prevents ketosis. It also inhibits the breakdown of proteins for energy as they are primary sources of energy.

Hence from the above discussion we can say that option B is the correct answer.

Note: The carbohydrates can be further classified into simple and complex carbohydrates on the basis of their chemical structure and degree of polymerization. It is said to be healthy to use vitamins, carbohydrates and all other organic nutrients in their normal forms.