Which of the Following Statements Regarding Neurotransmitters Is TRUE

Which of the following statements regarding neurotransmitters is TRUE?

A) Acetylcholine is broken down by enzymes present on postsynaptic cell membranes.
B) Acetylcholine that is released at synapses binds to adrenergic receptors in the postsynaptic cell membrane.
C) Catecholamines are the most abundant neurotransmitters in the central nervous system.
D) Opiate drugs,such as morphine,are antagonists of a class of neurotransmitters called endorphins.
E) Gamma-aminobutyric acid (GABA) is a major excitatory transmitter in the central nervous system.