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
[{'content': 'All of the following are bactericidal drugs except? \nSelect and explain. \nA. Ethambutol, B. Isoniazid, C. Rifampicin, D. Pyrazinamide', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Ethambutol All first line drugs are tuberculocidal except ethambutol which is tuberculostatic. Tuberculocidal - Rifampin, INH, streptomycin, pyrazinamide. Tuberculostatic - Ethambutol, PAS, cycloserine, thioacetazone.", 'role': 'assistant'}]