Which of the following stimulates the pancreas to secrete insulin?

A. Ketoacids: This is incorrect. While ketoacids are a by-product of fat metabolism that occurs when insulin is low, they do not directly stimulate insulin secretion. B. Hyperglycaemia: This is correct. Elevated blood glucose levels (hyperglycaemia) directly stimulate the pancreas to secrete insulin to help lower blood glucose levels. C. Hypoglycaemia: This is incorrect. Low blood glucose levels (hypoglycaemia) would reduce insulin secretion and might increase glucagon secretion to raise blood glucose levels. D. Glucagon: This is incorrect in the context of directly stimulating insulin secretion. Glucagon is a hormone secreted by the alpha cells of the pancreas when blood glucose levels are low. Its primary role is to increase blood glucose levels by stimulating glycogenolysis and gluconeogenesis in the liver.