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
Resistance to methicllin is acquired by: 
Select and explain. 
A. Increased B-lactamase production, B. Induction of channels that pump out the drug, C. Alteration in penicillin binding protein, D. Decreased absorption of drug in the gut
C: Alteration in penicillin binding protein
Answer: C: Alteration in penicillin binding protein 
Explanation: Methicillin, Nefcillin, oxacillin are B lactamse resistant penicillins. Resistance can occur only if there is alteration of penicillin binding protein.