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 30-year old male complains of loss of erection; he has low testosterone and high prolacting level in blood; What is the likely diagnosis - \nSelect and explain. \nA. Pituitary adenoma, B. Testicular failure, C. Craniopharyngioma, D. Cushing's syndrome", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]