The transition between the absorptive and fasting phase occurs when

A) a person begins to weaken from lack of food.
B) about 4 hours have passed since the last meal.
C) the body stops deriving its energy from the fuels still circulating in the blood from the previous meal.
D) the brain stops deriving its energy from glycogen.
E) the brain stops deriving its energy from the glycogen stored in neurons from the previous meal.

Answer: C