This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: JIPMER 2017, Subject name: Pharmacology
Which of the following antimicrobial shows time dependent killing? 
Select and explain. 
A. Ofloxacin, B. Amikacin, C. Penicillin, D. Ciprofloxacin
C: Penicillin
Answer: C: Penicillin 
Explanation: Bactericidal agents can be divided into two groups: Agents that exhibit concentration-dependent killing (e.g. aminoglycosides and quinolones) Agents that exhibit time-dependent killing (e.g., b lactams and vancomycin).