Who is doing work.
A Becky studies for her test. B Bob carries a baby across the hall C sally pushes a stroller around the block D Ben holds a plank for one minute

C sally pushes a stroller around the block

Explanation: Sally dose not have to push the stroller around the block she just put the work in and done it

a) electrical > light, sound, and thermal< < < <

) the mechanical energy of the firefighter moving.< < < < a) electrical > light, sound, and thermal< < < <

c) both a and b.

the answer is a. hope this .