One difference between mechanical and electromagnetic waves is that mechanical waves need a medium to pass through (solid, liquid, gas). EM waves can travel through matter or though a vacuum. In regards to telecommunications, EM waves can be radio waves, these are used in TV's, phones, computers, radios. Mechanical waves somewhat relate to this since radios produce sound;so an EM wave would turn into a mechanical vibration inside a speaker then sound would be produced.
I believe the correct answer to the question is D. This answer choice makes the most sense given the context. Also, since RNA is less stable than DNA, it mutates more often.