A nonproprietary drug contains which of the following?

A nonproprietary drug, often referred to as a generic drug, is a medication that is not protected by a trademark and is considered equivalent to its branded counterpart in terms of dosage form, strength, and intended use. The term "nonproprietary" highlights a drug’s generic identity that is defined by its active ingredients rather than its specific brand.

Option B, which mentions biologicals or substances of glandular origin, is the correct choice because it aligns with the definition of nonproprietary drugs. Such drugs can include a variety of compounds, including those derived from sources like glands or other biological materials. These substances are recognized in pharmacopoeias and can be marketed without exclusive brand names, indicating a breadth of acceptable ingredients that can fall under the "nonproprietary" classification.

Other options do not encompass the full scope of what nonproprietary drugs may contain. For example, focusing solely on controlled substances or prescription-only ingredients does not accurately reflect the variety of nonproprietary drugs available. Similarly, limiting the classification to only over-the-counter medications excludes the larger category of biologicals and other non-generic compounds, failing to recognize the comprehensive nature of nonproprietary drugs.