Consider that the room is a closed system. Ryan uses the chemical energy in his muscles to create the energy of motion. He uses this energy of motion to pull the string on the clapper of a bell to produce a sound. Sound fills the room.

Which describes the energy in this room?

A. While energy has taken different forms, total energy remains the same.

B. As energy changes forms, total energy decreases.

C. While energy is changing forms, total energy at first increases, then decreases.

D. As energy changes forms, total energy increases.