Which of the following is a Schedule II controlled substance?

Sufentanil is classified as a Schedule II controlled substance due to its high potential for abuse and the risk of severe psychological or physical dependence. Schedule II substances are those that, while having accepted medical uses, also require careful regulation due to their potential for misuse. Sufentanil is an opioid used primarily for pain management in clinical settings, especially during surgical procedures, and its potency makes it a target for abuse.

In contrast, the other substances listed are classified differently. Diazepam and Alprazolam, although they are also controlled substances, fall under Schedule IV, which indicates a lower potential for abuse relative to Schedule II substances. Ibuprofen is an over-the-counter medication with no abuse potential and is not classified as a controlled substance at all. Understanding the classifications of these substances is crucial for recognizing the legal and pharmacological implications of their use in clinical practice.