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': 'Why TB patient is recommend a regimen of 4 drugs on 1st visit - \nSelect and explain. \nA. To avoid emergence of persistors, B. To avoid side effects, C. To cure early, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: During first visit (intensive phase) 3 or more drugs are combined to kill off as many bacilli as possible . The more rapidly the bacilli are killed initially, the less likely are "persisters" to emerge. The risk of relapse is also lessened. Ref: PARK&;S TEXTBOOK OF PREVENTIVE AND SOCIAL MEDICINE 23rd edition , Page :187', 'role': 'assistant'}]