Which of the Following Is the Ultimate Action That Causes $\beta$

Multiple Choice

Which of the following is the ultimate action that causes release of insulin from pancreatic $\beta$ -cells?

A) opening of ATP-gated K⁺ channels
B) closing of ATP-gated K⁺ channels
C) catabolism of glucose resulting in increased ATP
D) opening of voltage gated Ca²⁺ channels leading to decreased cytosolic Ca²⁺
E) opening of voltage gated Ca²⁺ channels leading to increased cytosolic Ca²⁺