This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anti Microbial, Subject name: Pharmacology
[{'content': 'H1N1 influenza prophylaxis \nSelect and explain. \nA. Oseltamivir, B. Zanamivir, C. Amantadine, D. Rimantadine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. a. OseltamivirRef: Goodman Gilman 12th E/P1114Drug of Choice for Treatment of InfluenzaInfluenza A and BOseltamivir resistant influenza A and BOral Oseltamivir 75 mg BD for 5 daysInhalational Zanamivir 75 mg OD for 7 daysDrug of Choice for Prophylaxis of InfluenzaInfluenza A and BOseltamivir resistant influenza A and BOral Oseltamivir 10 mg BD 5 daysInhalational Zanamivir 10 mg OD 7 days', 'role': 'assistant'}]