Considering the law of conservation of energy, we believe that a super-duper bouncy ball should keep bouncing - forever. Yet, we know that it eventually stops.

How is energy conserved or is it?

Bouncing Balls GIFs | Tenor

a
A. Some is converted into sound energy and escapes into the surroundings.
b
B. Some is converted into thermal energy and escapes into the surroundings.
c
C. Neither A. or B.
d
D, Both A. and B.

not A if it's in a vacuum

so, B only