PLEASE HELP QUICK
Engines transform the energy in fuel into mechanical energy, heat, and sound.
Why is some of the energy in fuel always transformed into heat?
A.It is possible to build an engine that runs without heating up, but it would be expensive.
B. It is not possible to build an engine that runs without heating up.
C.It is possible to build an engine that runs without heating up, but technology has not advanced enough for it yet.
D.Engines can run cold, but it damages the engine. Most engines are heated up for this reason.