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: Social & Preventive Medicine
[{'content': 'In house with 9 susceptible individuals 1 gets infected and other two get infected after two days what is the secondary attack rate ? \nSelect and explain. \nA. 25%, B. 33%, C. 50%, D. 65%', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., 25%", 'role': 'assistant'}]