This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pharmacokinetics, Subject name: Pharmacology
Which of the following drug is inactive when given as oral dosage form ? 
Select and explain. 
A. Clonidine, B. Enalapril, C. Streptomycin, D. Morphine
B: Enalapril
Answer: B: Enalapril 
Explanation: * Prodrugs are the drugs which are inactive and are activated in the body. * Enalapril is an ACE inhibitor and is a prodrug. * Impoant examples of prodrugs include: All ACE inhibitors (except captopril and lisinopril) Prefer Prednisone Proton pump inhibitors Proguanil Doing Dipivefrine M Mercaptopurine Methyldopa Minoxidil D Levo-Dopa In Irinotecan Clinical Cyclophosphamide Clopidogrel Carbimazole Subjects Sulfasalazine