This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology, Subject name: Microbiology
H5N1 is strain of - 
Select and explain. 
A. An flu, B. New vaccine againts AIDS, C. Aent for japanese encephalitis, D. Causes chickengunya fever
A: An flu
Answer: A: An flu 
Explanation: H5N1 is the strain of an influenza REF:<\p> MICROBIOLOGY ANANTHA NARAYANAN NINTH EDITION PAGE.502