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': 'Optimal /effective duration of short course therapy for pulmonary TB is: \nSelect and explain. \nA. 6 months, B. 9 months, C. 12 months, D. 18 months', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans: a (6 months) Ref: Park, 19th ed, p. 157Short course regimes of 6 months duration are highly effective, of low toxicity and well tolerated.These potent regimes are based on a initial intensive phase with four drugs--INH, rifampicin,Pyrizinamide, supplemented by either streptomycin or ethambutol for a period of 2 months, followed by 2 drugs in continuation phase.The treatment must be fully supervised and monitored mainly by bacteriological examination.', 'role': 'assistant'}]