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': 'A village has a total of 100 under-five children. The coverage with measles vaccine in this age group is 60%. Following the occurrence of a measles case in a child after a visit outside, twenty six children developed measles. The secondary attack rate ofmeasles is - \nSelect and explain. \nA. 25%, B. 40%, C. 50%, D. 65%', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., 65 %", 'role': 'assistant'}]