Which of the following medications is prescribed for anxiety?

Xanax is a medication that is specifically classified as a benzodiazepine, which is commonly prescribed for the treatment of anxiety disorders. Its active ingredient, alprazolam, works by affecting the brain's neurotransmitters to help reduce anxiety levels and promote relaxation. This makes it a suitable option for patients who struggle with anxiety, as it provides quick relief from the symptoms associated with anxiety disorders.

In contrast, the other medications listed do not serve the purpose of treating anxiety. Digoxin is primarily used to treat heart conditions such as atrial fibrillation or heart failure. Naproxen is a nonsteroidal anti-inflammatory drug (NSAID) used to relieve pain and inflammation, and Quinidine is an antiarrhythmic medication used to treat certain types of irregular heartbeats. None of these medications are indicated for the treatment of anxiety, which reinforces why Xanax is the correct answer.