A. because is, is the action of the library
C.) is the correct use of "who's." "Who's" is a contraction of who and is. In each sentence, instead of saying who's, say who is.
(ex. "Who is turn is it..." doesn't sound right.).
The other three sentences are incorrect; they need "whose" instead which is a <span>determiner or pronoun showing possession. </span>
Parallelism is the repetition of the same form of words or verbs in a sentence is explained as parallelism.
All the sentences given in the questions give the example of parallelism. It contains the repetition of the same form of words. In the first sentence qualities of a morning is mentioned. In second sentence all the food items are written.
<span>They are going out to celebrate Caesar's victory over his rival Pompey</span>