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
Which of the following is not a pro-drug? 
Select and explain. 
A. Becampicillin, B. Levodopa, C. Penicillin, D. Enalapril
C: Penicillin
Answer: C: Penicillin 
Explanation: A prodrug is a pharmacological substance that is administered in an inactive or paially active form, and is subsequently conveed to an active pharmacological agent (drug) through normal metabolic processes (bioactivation). Levodopa changes to dopamine Becampicillin to ampicilline and Enalapril to enalaprilat