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: Medicine
[{'content': 'True about measles is/are  a) Incubation period (I.P.) is 10-12 days  b) Confunctivitis common  c) Rash starts on abdomen  d) Koplik spots are seen on fundus examination \nSelect and explain. \nA. ab, B. bc, C. cd, D. bd', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]