Which of the following best describes a lotion?

A lotion is best described as a liquid suspension that protects, cools, or cleanses the skin. This characteristic highlights its primary function as a topical application, which can hydrate the skin, provide a soothing sensation, and serve as a barrier against irritants or pollutants. Lotions typically have a lighter consistency compared to creams or ointments, which makes them ideal for widespread application across larger areas of the skin.

Other forms of medication serve different purposes; for example, a thick paste is generally more associated with ointments that are used for specific therapeutic effects rather than broad skincare. Solid forms of medication are tailored for oral use and do not apply to the topical function of lotions, while injectable medications are entirely different in application and route of administration. Each of these alternatives does not align with the definition of a lotion, further emphasizing the accuracy of the correct choice.