This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Pharmacology
Drug X which inhibit the binding of RANKL to its receptor (RANK) in osteoporosis: 
Select and explain. 
A. Teriparatide, B. Alendronate, C. Denosumab, D. Estrogen
C: Denosumab
Answer: C: Denosumab 
Explanation: Ans. C. DenosumabOsteoclasts express RANK receptor which on stimulation causes resorption of bone. Denosumab is monoclonal antibody which inhibit the binding of ligand to the receptor and thus play a role in osteoporosis.