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
All of the following drugs are primarily bacteriostatic except 
Select and explain. 
A. Sulphonamide, B. Chloramphenicol, C. Ethambutol, D. Rifampicin
D: Rifampicin
Answer: D: Rifampicin 
Explanation: None