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
The following is not a penicillinase resistant penicillin- 
Select and explain. 
A. Methicillin, B. Ampicillin, C. Oxacillin, D. Nafcillin
B: Ampicillin
Answer: B: Ampicillin 
Explanation: Ans. is b i.e., Ampicillin