The term "lost energy" often refers to energy transferred to the surrounding environment in the form of

The term 'lost energy' often refers to energy transferred to the surrounding environment in the form of heat. Energy can neither be created nor destroy but it can be transformed to another form or transferred. Energy is often lost because no system can convert all its input energy into useful work. The energy lost is usually released into the surrounding environment in form of heat.  

Ithink the answer is c. i’m not sure though i’ll notify you when i have an exact answer!

The correct answer:   [c]:   "cell phone call" .