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': 'Sternal edema is seen in - \nSelect and explain. \nA. Measles, B. Mumps, C. Diphtheria, D. Varicella', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]