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
Which is not true about measles vaccine? 
Select and explain. 
A. Egg culture, B. Freeze dried, C. Reconstituted vaccine should be used within one hour, D. Given after 9 months of age
A: Egg culture
Answer: A: Egg culture 
Explanation: None