Question

Sentence syntax should be varied to 

Answer 1

Answer:

C. keep readers’ interest.

(edge says)

Answer 2

C. To keep the reader's interest. Syntax is the structure of a sentence (how long it is and how it is punctuated). It does not really deal with the specific, individual words that an author chooses--so a, b and c would not be the answer because they deal with the actual words in the text.