Final answer:
The acceleration of gravity (g) is determined by a planet's or moon's mass and radius, with the universal gravitational constant factoring into the calculation.
Step-by-step explanation:
The acceleration of gravity (g) on the surface of a planet or moon is determined by its mass and radius. The value of g is calculated using the formula g = GM/r^2, where G is the universal gravitational constant, M is the mass of the planet or moon, and r is its radius. Hence, the correct answer is C. Its mass and radius.
The value of g can vary slightly if the material below the surface varies from point to point. Due to these variations, g is not the same at every point on a planet's surface. Furthermore, variations in g can also be influenced by the planet's rotation, which affects the effective gravitational pull on objects at the equator compared to the poles.