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: Unknown
All of the following are bactericidal drugs except- 
Select and explain. 
A. Ethambutol, B. Isoniazid, C. Rifampicin, D. Pyrazinamide
A: Ethambutol
Answer: A: Ethambutol 
Explanation: Ans. is 'a' i.e., Ethambutol o All first-line drugs are tuberculocidal except ethambutol which is tuberculostatic. Tuberculocidal - Rifampin, INH, streptomycin, pyrazinamide. Tuberculostatic - Ethambutol, PAS, cycloserine, thioacetazone.