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: Pharmacology
Drug of choice for prophylaxis of TB is ? 
Select and explain. 
A. Rifampicin, B. Isoniazid, C. Pyrizinamide, D. Streptomycin
B: Isoniazid
Answer: B: Isoniazid 
Explanation: Ans. is 'b' i.e., Isoniazid o Isoniazid is the drug of choice for prophylaxis of TB.