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: Medicine
[{'content': 'A common cause of Primary hyperparathyroidism is \nSelect and explain. \nA. Multiple parathyroid adenomas, B. Solitary parathyroid adenoma, C. Adrenal hyperplasia, D. Ectopic PTH production', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]