People who have depression may have low levels of the neurotransmitter

A) serotonin.
B) dopamine.
C) GABA.
D) acetylcholine.

Neurotransmitter

A chemical substance that transmits nerve impulses across a synapse between two neurons, playing a crucial role in the functioning of the nervous system.

Serotonin

A neurotransmitter in the brain that affects mood, emotion, sleep, and appetite, often associated with feelings of well-being and happiness.