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
Optimal /effective duration of short course therapy for pulmonary TB is: 
Select and explain. 
A. 6 months, B. 9 months, C. 12 months, D. 18 months
A: 6 months
Answer: A: 6 months 
Explanation: 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.