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
About measles true is ? 
Select and explain. 
A. Incubation period is 5 days, B. Otitis media is the most common complication, C. Caused by ohomyxovirus, D. Large number of carriers
B: Otitis media is the most common complication
Answer: B: Otitis media is the most common complication 
Explanation: Ans. is 'b' i.e., Otitis media is the most common complication Measles is caused by a RNA virus of paramyxovirus family. The only source of infection is a case of measles, carriers are not known to occur.