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
Which of the following drugs acts by inhibiting DNA dependant RNA synthesis in mycobacteria? 
Select and explain. 
A. Ciprofloxacin, B. INH, C. Rifampicin, D. Ethambutol
C: Rifampicin
Answer: C: Rifampicin 
Explanation: Rifampicin is a bactericidal drug which acts by inhibiting DNA dependent RNA synthesis. INH is a sulfa drug which acts by inhibition of synthesis of mycolic acid, a fatty acid component of mycobacterial cell wall. Ethambutol acts by inhibiting arabinogalactan synthesis and by interfering with mycolic acid incorporation in mycobacterial cell wall.