Correct Option: A

Vitamin D (ergocalciferol or antirachitic vitamin) which is commonly known as ‘sunshine vitamin’ regulates the absorption of calcium & phosphorus from gastrointestinal tract and hence helping in the normal growth of bones & teeth. Its deficiency disturbs the calcium & phosphorus absorption and hence deficiency of these minerals in the body causes soft bones where bones become curved and fragile (osteomalacia) and teeth decay.