Answer :

The correct answer is: c. Librium Explanation: 1. Librium is a controlled substance because it contains chlordiazepoxide, which is a type of benzodiazepine. 2. Controlled substances are drugs that have the potential for abuse and dependence, so they are regulated by the government to prevent misuse. 3. Vistaril, Zoloft, and Lexapro are not controlled substances. Vistaril is an antihistamine used for anxiety, Zoloft is an antidepressant, and Lexapro is also an antidepressant.

Answer:

Librium is a controlled substance among the listed antianxiety drugs.

Explanation:

Librium is classified as a controlled substance because it contains the active ingredient chlordiazepoxide, which belongs to the benzodiazepine class of medications. Benzodiazepines have a potential for abuse and dependence, leading to their regulation as controlled substances to prevent misuse and ensure they are used appropriately under medical supervision.