This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Myxo Viruses, Subject name: Microbiology
Swine flu is caused by? 
Select and explain. 
A. H1N1, B. H5N1, C. H3N1, D. H3N3
A: H1N1
Answer: A: H1N1 
Explanation: ANSWER: (A) H1N1REF: See APPENDIX-69 for details of "H1N1 influenza"Repeat (**)