Which of the following drugs is considered a Schedule V substance?

Cough syrup with codeine is classified as a Schedule V controlled substance because it contains a lower concentration of codeine compared to other formulations, making it less potent and having a lower potential for abuse. Schedule V substances are defined as having accepted medical uses and a lower potential for dependence relative to substances in higher schedules.

Cough syrups that contain a certain amount of codeine are commonly prescribed for cough relief, which is why they fall under this category. The balance between therapeutic benefits and the risks of abuse and dependence is what determines its Schedule V classification. The presence of codeine does not eliminate its medical applications but signifies that it can be used safely under healthcare supervision within the appropriate dosage guidelines.