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
The infectivity, of chicken pox lasts for - 
Select and explain. 
A. Till the last scab falls off, B. 6 days after onset of rash, C. 3 days after onset of rash, D. Till the fever subsides
B: 6 days after onset of rash
Answer: B: 6 days after onset of rash 
Explanation: Ans. is 'b' i.e., 6 days after onset of rash