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
Which is the fastest calcium lowering agents ? 
Select and explain. 
A. Calcitonin, B. Plicamycin, C. Etidronate, D. Zoledronate
A: Calcitonin
Answer: A: Calcitonin 
Explanation: None