This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Vitamin beneficial in osteoporosis in combination with Vitamin D is: 
Select and explain. 
A. Vitamin E, B. Vitamin A, C. Vitamin K, D. Vitamin B
C: Vitamin K
Answer: C: Vitamin K 
Explanation: None