Final answer:
A solid drug dispersed within a liquid is known as a suspension, a heterogeneous mixture where particles can settle upon standing. The correct answer is (c) Suspension.
Step-by-step explanation:
A solid drug dispersed within a liquid is called a suspension. A suspension is a heterogeneous mixture in which the solid particles are dispersed throughout a liquid but, unlike a solution, these particles can settle upon standing. This is observable in everyday life with mixtures like mud in water. In contrast, an emulsion is a type of colloid where droplets of one liquid are dispersed within another liquid, such as oil in water. A solution, by definition, is a homogeneous mixture where a solute dissolves in a solvent, resulting in a clear and uniform composition that won't settle, like saltwater. Therefore, the correct answer to the student's question is (c) Suspension, denoting a mixture with larger particles that can separate upon standing.