This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vitamins and Minerals, Subject name: Biochemistry
Steroidal prohormone is: 
Select and explain. 
A. Vitamin A, B. Vitamin C, C. Vitamin D, D. None of these
C: Vitamin D
Answer: C: Vitamin D 
Explanation: Ans. C. Vitamin DVitamin D is a steroid prohormone. It is represented by steroids that occur in animals, plants and yeast. Active form of the hormone is 1, 25-dihydroxy vitamin D3 (1, 25-(OH)2D3, also termed calcitriol). Calcitriol functions primarily to regulate calcium and phosphorous homeostasis.