**Core Concept**
Sulfonylureas are a class of oral hypoglycemic agents that work by stimulating insulin release from the pancreatic beta cells. They bind to specific receptors on the surface of these cells, leading to closure of potassium channels and subsequent depolarization.

**Why the Correct Answer is Right**
Sulfonylureas act by binding to the sulfonylurea receptor (SUR1), a subunit of the ATP-sensitive potassium channel (KATP). This binding causes a conformational change in the channel, leading to its closure. As a result, the cell membrane depolarizes, opening voltage-dependent calcium channels, and increasing intracellular calcium. The increased calcium concentration triggers the exocytosis of insulin granules, resulting in insulin release. This mechanism is responsible for the hypoglycemic effect of sulfonylureas.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because sulfonylureas do not directly stimulate the insulin receptor or mimic insulin's action on the insulin receptor substrate (IRS) to produce hypoglycemia.

**Option B:** This option is incorrect because sulfonylureas do not inhibit glucagon secretion directly, although they may indirectly affect glucagon levels by reducing blood glucose concentrations.

**Option C:** This option is incorrect because sulfonylureas do not directly inhibit glucose production in the liver by inhibiting key enzymes involved in gluconeogenesis.

**Clinical Pearl / High-Yield Fact**
It is essential to remember that sulfonylureas can cause hypoglycemia due to their mechanism of action, and this effect can be potentiated by other medications that also increase insulin release, such as nateglinide and repaglinide.

**Correct Answer: A.**