The correct response is:
Mass is eliminated when equating gravitational potential energy with kinetic energy.
This is because, in the conservation of mechanical energy, the initial gravitational potential energy (PE) of the ball is converted into kinetic energy (KE) as it falls. The equations for gravitational potential energy (PE = mgh) and kinetic energy (KE = 0.5mv²) both contain the mass (m). When you set these two expressions equal to each other (mgh = 0.5mv²) to analyze the conservation of energy, you can cancel out the mass (as long as it is not zero), which shows that the conservation of mechanical energy does not depend on the mass of the object.