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': "Giant cell (Hecht's) pneumonia is due to \nSelect and explain. \nA. CMV, B. Measles, C. Malaria, D. P. carinii", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]