Which of the following represents a common benzodiazepine?

The correct choice, which is diazepam, represents a common benzodiazepine due to its well-established use in the treatment of various conditions such as anxiety, muscle spasm, and seizure disorders. Benzodiazepines are a class of psychoactive drugs characterized by their calming effects on the central nervous system. Diazepam, in particular, is known for its efficacy in managing symptoms related to acute stress reactions and is also used as a sedative prior to medical procedures.

This makes diazepam distinct from the other options listed. Sertraline, fluoxetine, and metoprolol belong to different drug classes. Sertraline and fluoxetine are both selective serotonin reuptake inhibitors (SSRIs) used primarily for treating depression and anxiety disorders. Metoprolol is a beta-blocker commonly prescribed for hypertension and other cardiovascular conditions. Thus, understanding these classifications highlights why diazepam is the representative of benzodiazepines among the other choices.