Which of the following sentences has an error in agreement? a. don’t the young man belong in the computer room? b. the acceptance letter was sent to the wrong student. c. the book at the front desk is his, not mine. d. the dogs dug deep holes in the school’s front yard.

sentence lenght varies according to word choice.you select which word to use and that will require to use other expressions that collocate with the word chosen.sentence length will vary   according to the choice of words you make to express your ideas.  

your answer is going to be part c