**Core Concept**
Sulfonylureas are a class of oral hypoglycemic agents that stimulate insulin release from the pancreatic beta cells. They work by binding to a specific receptor on the pancreatic beta cell, which triggers the closure of ATP-sensitive potassium channels, leading to cell depolarization and insulin secretion.

**Why the Correct Answer is Right**
Tolbutamide, a first-generation sulfonylurea, has a relatively low potency. Second-generation sulfonylureas, such as glimepiride and glipizide, have higher potency. Among these, glimepiride has been shown to have the highest insulinotropic potency due to its strong binding affinity to the SUR1 receptor and its ability to increase insulin release even at low glucose concentrations. This is attributed to its lipophilic nature, which allows it to readily cross the cell membrane and interact with the SUR1 receptor.

**Why Each Wrong Option is Incorrect**
**Option A:** Tolbutamide has lower potency compared to glimepiride and glipizide.
**Option B:** Glibenclamide (also known as glyburide) has a higher potency than glimepiride but is not as potent as glimepiride in terms of insulin release at low glucose concentrations.
**Option D:** Chlorpropamide has the longest duration of action but lower potency compared to glimepiride.

**Clinical Pearl / High-Yield Fact**
Glimepiride's high potency and efficacy in stimulating insulin release make it a popular choice for managing type 2 diabetes, particularly in patients who are resistant to other sulfonylureas.

**Correct Answer:** C. Glimepiride.