Which medication increases beta pancreatic cell sensitivity to glucose (insulin secretagogue)?

SULFONYLUREAS (glipizide, glyburide, glimepiride) stimulate insulin secretion by binding to ATP-sensitive K+ channels on beta pancreatic cells, causing depolarization and insulin release — they INCREASE SENSITIVITY/STIMULATION of beta cells to secrete insulin. METFORMIN primarily decreases HEPATIC GLUCOSE PRODUCTION and improves peripheral insulin sensitivity — it does NOT stimulate beta cells. So sulfonylureas specifically increase beta cell insulin secretion. B is correct.