D. parallel structure just means that all of your verbs in the comma series line up in regards to tenses, here. in choice D, it's "BE friendly," "INTRODUCE yourself," and "SMILE." these are all present tense verbs.
the rest of the choices don't match--"exercise" and "stretching" are two different verb forms in choice A, "to go to the library" is the odd one out in choice B, ane "to build" doesn't match with the "-ing" verbs in choice C.
Answer:
The question above refers to Computer Back up.
Explanation:
The backup of the data stored in a computer is what allows a clean starting point, inside the machine, which allows the user to have a great security of the files stored by him. In that case, as the question above states, returning files to the computer will be easier than redoing everything manually. Back up is a security strategy, where the user copies all important files to a storage device, where the files can be recovered, in case the computer needs to be restored and this forces the deletion of the original files.
