This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Protein Synthesis Inhibitors, Subject name: Pharmacology
Which of the following drugs acts by blocking RNA transcription? 
Select and explain. 
A. Rifampicin, B. Streptomycin, C. Isoniazid, D. Chloramphenicol
A: Rifampicin
Answer: A: Rifampicin 
Explanation: DRUG MECHANISM Rifampicin Inhibit transcription of RNA Isoniazid Act on mycobacterial membrane Streptomycin Inhibit protein synthesis Chloramphenicol Inhibit protein synthesis