This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
[{'content': 'Amplifier for Japanese encephalitis – \nSelect and explain. \nA. Horse, B. Pigs, C. Dogs, D. Monkey', 'role': 'user'}, {'content': 'Answer: B \nExplanation: In Japanese encephalitis\nPigs\xa0→ Amplifiers.\nCattle and buffalos → Mosquito attractants Man → Incidental dead-end host Herons → Reservoir hosts', 'role': 'assistant'}]