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: Social & Preventive Medicine
[{'content': 'Which is not true about measles vaccine? \nSelect and explain. \nA. Egg culture, B. Freeze dried, C. Reconstituted vaccine should be used within one hour, D. Given after 9 months of age', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]