This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Chemotherapy, Subject name: Pharmacology
Which of the following drug is bactericidal? 
Select and explain. 
A. Sulfonamides, B. Erythromycin, C. Chloramphenicol, D. Cotrimoxazole
D: Cotrimoxazole
Answer: D: Cotrimoxazole 
Explanation: Primarily bactericidal: Penicillins Cephalosporins Aminoglycosides Vancomycin Polypeptides Nalidixic acid Rifampin Ciprofloxacin Isoniazid Metronidazole Pyrazinamide Cotrimoxazole ESSENTIALS OF MEDICAL PHARMACOLOGY K.D.TRIPATHI SIXTH EDITION PAGE NO:669