Frank Tells His Friend That He His Madly in Love

Frank tells his friend that he his madly in love with Marie, and that it feels like he's high. There is some element of truth to that because Frank's brain

A) is releasing the neurotransmitter, serotonin.
B) is using glucose at a faster rate.
C) areas that experience reward and release dopamine are active.
D) chemicals are completely out of balance, much like a heroin addict.