What does mass measure in an object?

The correct answer is that mass measures the amount of matter present in an object. Mass is a fundamental property of physical bodies that quantifies the quantity of matter within them, irrespective of the object's location or the gravitational force acting on it. It is an intrinsic property, meaning it does not change based on external conditions like gravity or the environment.

When considering the other options, force refers to an interaction that causes a change in an object's motion, volume is the amount of three-dimensional space an object occupies and is not synonymous with mass, and weight is a measure of the force exerted on an object due to gravity, which varies depending on the gravitational field strength (making it dependent on location, such as on Earth). Hence, mass distinctly represents the total matter in an object, making option C the correct choice.