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
All of following are true about measles except - 
Select and explain. 
A. Maximum incidence in 6m-3 year age group, B. Best age for immunization is 9-12 months, C. Secondary attack rate is 30%, D. I.P. = 7-14 days
C: Secondary attack rate is 30%
Answer: C: Secondary attack rate is 30% 
Explanation: None