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
'H5 Nl' may be best described as a: 
Select and explain. 
A. Bird flu virus, B. Vaccine for HIV, C. Agent for Japanese encephalitis, D. New strain of Plasmodium falciparum
A: Bird flu virus
Answer: A: Bird flu virus 
Explanation: H5N1 is the An Flue a type of Influenza A virus, also called the Bird Flu Virus. Ref: Molecular Medicine: An Introductory Text By Trent, 3rd Edition, Pages 209-10; Clinical Infectious Disease By Schlossberg, 2008, Page 1290