Which of the Following Is True of Insulin and Glucagon

Which of the following is true of insulin and glucagon?

A) Insulin and glucagon regulate the level of calcium in the blood.
B) Insulin and glucagon maintain normal levels of blood glucose in the fasting state.
C) Secretion of insulin and glucagon is regulated by the pituitary gland.
D) Insulin and glucagon have opposite effects on blood glucose but work together to maintain homeostasis.