The correct answer to the question is option 2, Vitamin D. Rickets is a disease that mainly affects children and is caused by a deficiency of Vitamin D in the body.

Vitamin C, mentioned in the first option, is not responsible for causing rickets. Vitamin C is essential for collagen synthesis and the immune system, and its deficiency leads to scurvy, a different condition.

Vitamin A, mentioned in the third option, is important for vision, immune function, and cell growth. However, its deficiency does not cause rickets. A deficiency of Vitamin A can lead to night blindness and other problems associated with the eyes.

Vitamin B, mentioned in the fourth option, is a group of several different vitamins (B1, B2, B3, etc.) that play various roles in the body. None of the B vitamins, individually or as a group, are responsible for causing rickets.

In summary, rickets is caused by a deficiency of Vitamin D, which is essential for bone health and calcium absorption. It is important to ensure an adequate intake of Vitamin D, either through sunlight exposure or through dietary sources, to prevent the development of rickets in children.