What is the primary purpose of an instrument that measures volume?

The primary purpose of an instrument that measures volume is to determine the space occupied by a liquid. Volume is a measure of how much three-dimensional space a substance, such as a liquid, occupies. Instruments like graduated cylinders, measuring cups, and volumetric flasks are specifically designed to provide precise measurements of liquid volume, allowing for accurate preparation and use in experiments, cooking, and various scientific applications.

In contrast, measuring mass involves assessing the amount of matter in an object and typically requires scales, while density is a derived measurement calculated by dividing mass by volume, and pressure is related to force per unit area, often measured using barometers or pressure gauges. Thus, option C accurately describes the function of a volume-measuring instrument, focusing solely on the capacity of space occupied by liquids.