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 are prodrugs ? 
Select and explain. 
A. Mercaptopurine, B. Dipivefrine, C. Enalapril, D. All of these
D: All of these
Answer: D: All of these 
Explanation: - Among given options Enalapril, Dipivefrine and Mercaptopurine are prodrugs.