An example of an adulterated drug is:

A medication that has an unapproved color additive is classified as adulterated because it fails to meet the standards set by regulatory bodies, such as the FDA. The term “adulteration” refers to the inclusion of substances that may compromise the quality, purity, or safety of a drug. When a drug contains an unauthorized ingredient, it poses potential risks to patient safety, as these additives may have unknown effects or allergic reactions.

In this situation, the use of an unapproved color additive can suggest that the manufacturer did not adhere to the appropriate regulations regarding drug composition and labeling. This violation can lead to the drug being deemed unsafe for consumption, thus categorizing it as adulterated.

The other options illustrate various forms of drug quality issues, but they do not specifically align with the established definition of adulteration. For instance, an expired medication raises concerns about efficacy and safety, but it does not inherently include a harmful substance. Improperly stored medication may lead to degradation but does not meet the definition of adulterated regarding component quality. Likewise, an incorrect dosage concerns the drug's administration rather than its formulation or inherent safety.