Which of the following is an example of a depressant?

Benzodiazepines, such as Xanax and Valium, are classified as depressants because they work by enhancing the effects of the neurotransmitter gamma-aminobutyric acid (GABA) in the brain. This action results in a calming effect on the central nervous system. Depressants are substances that reduce the activity of the brain, leading to effects such as sedation, relaxation, and reduced anxiety.

In contrast, cocaine and amphetamines are stimulants, as they increase the activity of certain neurotransmitters, leading to heightened alertness, energy, and euphoria. Bath salts, which are synthetic drugs, can have stimulant-like effects as well, contributing to increased energy and alertness. Therefore, benzodiazepines clearly stand out as the only option that fits the definition of a depressant among the given choices.