The pendulum in a clock gradually slows down and stops moving after a while. A student states that its a loss of mechanical energy is evidence that energy is not always conserved. which two statements offer evidence that the clocks energy is conserved?

A. Friction between its moving parts transforms some of the pendulums mechanical energy into
other forms of energy

B. Conservation of energy happens only when the parts of the clock are oiled to reduce friction.

C. conservation of energy occurs because
the clocks matter is also conserved

D. the pendulum stops moving because all of its mechanical energy has been transformed into thermal energy and sound energy.