Joseph borrowed a book from a library. The library charges a fixed rental for the book and a late fee for every day the book was overdue. The expression below shows the charges Joseph paid for the book when he returned it x days after the due date: 2+0.25x

What does the coefficient of the expression represent?

A) the fixed rental for the book
B) the total late fee for the book
C) the late fee per day for the book
D) the number of days the book was overdue