Which of the following anti-TB drugs are bactericidal?

Correct option is A

Rifampicin and isoniazid are first-line bactericidal anti-TB drugs, killing actively multiplying bacilli. Ethambutol is bacteriostatic, while pyrazinamide is bactericidal but not paired in standard question.
Explanation of options: (a) ✔ Correct; INH + Rifampicin are the most potent bactericidal drugs in TB regimen. (b) ✘ Ethambutol is bacteriostatic; pyrazinamide is bactericidal, but not both together. (c) ✘ Streptomycin is bactericidal, PAS is bacteriostatic. (d) ✘ Clofazimine is used in leprosy and Ethionamide is bacteriostatic.