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
True statement about influenza A is - 
Select and explain. 
A. It has a double stranded segmented RNA, B. Pandemic are caused by antigenic drift, C. Nucelocapsid antibody is not specific, D. Hemagglutinin and Neuraminidase is strain specific
D: Hemagglutinin and Neuraminidase is strain specific
Answer: D: Hemagglutinin and Neuraminidase is strain specific 
Explanation: The viral or antigen is composed of at least two coded proteins hemagglutinins and neuraminidase. Both are strain-specific and is capable of great variation. REF:ANANTHANARAYAN AND PANIKER'S TEXTBOOK OF MICROBIOLOGY 9TH EDITION PAGE NO-498