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
What is the period of infectivity in measles ? 
Select and explain. 
A. From 7 days before to 7 days after the rash, B. From 3 days before to 5 days after the rash, C. From 9 days before to 12 days after the rash, D. From 5 days before to 9 days after the rash
B: From 3 days before to 5 days after the rash
Answer: B: From 3 days before to 5 days after the rash 
Explanation: None