The correct answer is B. Weight is the force of gravity on an object, and since each planet has a different gravitational force, the weight of an object will change depending on what planet it's on. For example, the moon (although not a planet) has only 1/6 the gravitational force that the earth does, so any object on the moon will weigh 6 times less than what it weighs on the earth. However, mass, volume, and density, will not change from place to place, regardless of gravitational force.