Answer:
(B) sound/kinetic
(E) Gravitational/kinetic
(F) mechanical/sound
Explanation:
(B) the useful energy transfer is sound but a by product of that is kinetic or mechanical energy because of the vibrations needed to make sound
(E) the useful energy transfer is Gravitational potential but a by product of that is kinetic or mechanical energy
(F) the useful energy transfer is kinetic or mechanical energy but the byproduct is noise and occasionally heat
