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
False about antigen drift - 
Select and explain. 
A. Causes pandemic, B. Occurs due to mutation, C. Occurs more frequently, D. Affected by previous antibodies
A: Causes pandemic
Answer: A: Causes pandemic 
Explanation: Repeated question please