This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable diseases, Subject name: Social & Preventive Medicine
[{'content': 'Isolation is not needed for measles due to - \nSelect and explain. \nA. There are healthy carriers, B. Carriers are convalascents, C. The infectivity in diseased is low, D. There are incubatory carriers', 'role': 'user'}, {'content': "Answer: D \nExplanation: Transmission directly from person to person by droplet infection from 4 days before onset of rash until 4days thereafter. REF. PARK'S TEXTBOOK OF PREVENTIVE AND SOCIAL MEDICINE 21ST EDITION. PAGE NO - 147", 'role': 'assistant'}]