A pendulum bob is pulled back and released. As it arrives to the lowest point of the swing, the bob collides with and sticks to a lump of clay and continues to swing. Assuming that air drag and pivot friction are negligible, which of the following is a correct statement about the energy in the bob-clay-Earth system? (A) The mechanical energy remains the same throughout the scenario. (B) The mechanical energy decreases at some point in this scenario. (C) The kinetic energy of the bob immediately before the collision equals the kinetic energy of the bob clay immediately after the collision. (D) The gravitational energy increases throughout the swing.