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: Microbiology
Which virus may produce incomplete progeny ? 
Select and explain. 
A. Influenza, B. Measles, C. Mumps, D. Polio
A: Influenza
Answer: A: Influenza 
Explanation: Ans. is 'a' i.e., Influenza When cells are infected with high dose of influenza virus, there is defective asembly during replication and the progeny virons are imcomplete and non-infective.This is called as Man - magnus phenomenon