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 one of the following does NOT act by increasing insulin secretion 
Select and explain. 
A. Glyburide, B. Repaglinide, C. Tolbutamide, D. Biguanide
D: Biguanide
Answer: D: Biguanide 
Explanation: None