Which dosage form is appropriate for oral, parenteral, or external use?

A solution is a dosage form that is composed of one or more solutes dissolved in a suitable solvent. It is versatile and can be administered through various routes, including oral, parenteral (injection), and external applications. For oral use, solutions can be taken directly or mixed with other substances; for parenteral use, they can be injected into the body; and for external use, they can be applied to the skin or mucous membranes.

This versatility makes solutions a common choice in pharmacy and medicine, as they can be formulated to suit different therapeutic needs and patient requirements. In contrast, other dosage forms like ointments are primarily designed for external application, pills are typically used for oral administration, and tinctures, although they can be ingested, are primarily for oral use as well. Thus, the solution's capability of accommodating multiple routes of administration solidly supports its selection as the appropriate choice for the question posed.