Answer:
0.237 (23.7 %)
Explanation:
The thermal efficiency of an engine is given by:

where
W is the useful work output of the engine
is the heat in input
Here we have:

and the work done is the total heat in input minus the heat exhausted:

So, the efficiency is
(23.7 %)
The correct answer is:
<span>C: in the protons and neutrons of an atom
In fact, the nuclear energy refers to the binding energy of the nucleons (protons and neutrons) of an atom. The protons and the neutrons are held together by the strong nuclear interaction, one of the four fundamental forces of nature, and the energy associated to this interaction is called nuclear energy.
</span>
The answer should be B.
Hope it helped you.
Those are in a solid state.