In the context of physics, what does the term 'mass' primarily refer to?

The term 'mass' primarily refers to the amount of matter an object contains. In physics, mass is a fundamental property of an object that reflects its quantity of matter, regardless of its volume or the forces acting on it. It is measured in kilograms (kg) and is a scalar quantity, meaning it has magnitude but no direction.

Mass is crucial in understanding the behavior of objects under various forces, such as gravity, where the mass of an object determines the gravitational force it exerts and experiences. While energy relates to the capacity to do work, and gravity pertains to the attraction between masses, neither of these directly defines what mass is. Additionally, volume pertains to the space an object occupies but does not signify the amount of matter it has. Hence, option B accurately captures the essence of mass in the context of physics.