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
[{'content': 'Both decreased bone resorption and increased bone formation are caused by: \nSelect and explain. \nA. Strontium ranelate, B. Ibandronate, C. Teriparatide, D. Calcitonin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]