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
An oral hypoglycemic agent is: 
Select and explain. 
A. Warfarin, B. Insulin, C. Glibeneclamide, D. Gluengon
C: Glibeneclamide
Answer: C: Glibeneclamide 
Explanation: None