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
One of the following drug is NOT effective against anaerobes - 
Select and explain. 
A. Penicillin, B. Chloramphenicol, C. Gentamicin, D. Clindamycin
C: Gentamicin
Answer: C: Gentamicin 
Explanation: Ans. is 'c' i.e., Gentamicin