This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: NEET Jan 2020, Subject name: Medicine
What is the first line of drug for post-menopausal Osteoporosis? 
Select and explain. 
A. Raloxifene, B. Oestrogen, C. Bisphosphonates, D. Combined OCP's
C: Bisphosphonates
Answer: C: Bisphosphonates 
Explanation: Treatment of post-menopausal Osteoporosis : Bisphosphonates First-line therapy. They increase bone density and reduce the risk for spine, hip and non-veebral fractures. Synthetic analogues of pyrophosphate that bind to the hydroxyapatite in bone and inhibit osteoclastic bone resorption.