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
[{'content': 'Influenza vacccines is administrered - \nSelect and explain. \nA. Intranasal instillation, B. Intradermal, C. Nasal drops, D. Intrathecal', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The earliest vaccine was the virus attenuated by repeated egg passage. These administered by intranasal instillation REF:ANANTHANARYANAN TEXTBOOK OF MICROBIOLOGY 9EDITION PGNO.504', 'role': 'assistant'}]