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
Secondary attack rate of chicken pox is - 
Select and explain. 
A. 60, B. 50, C. 90, D. 40
C: 90
Answer: C: 90 
Explanation: Secondary attack rate of chicken pox is high, upto 90%.