Jenny is in charge of ordering T-shirts for the math club at her school. If she paid $252 for 21 T-shirts, which of the following statements is true?
A. Jenny paid $252 for 21 T-shirts, which is a rate of $21 per T-shirt.
B. Jenny paid $252 for 21 T-shirts, which is a rate of $231 per T-shirt.
C. Jenny paid $252 for 21 T-shirts, which is a rate of $33 per T-shirt.
D. Jenny paid $252 for 21 T-shirts, which is a rate of $12 per T-shirt.