The cost of one pencil is $3, and the total cost of three pencils is $9. Which of the following is true?
A.
The number of pencils and the total cost are in a proportional relationship because the cost of zero pencils is $0 and each pencil costs $3.
B.
The number of pencils and the total cost are in a proportional relationship because the cost increases with the number of pencils.
C.
The number of pencils and the total cost are in a proportional relationship because the cost does not increase with the number of pencils.
D.
The number of pencils and the total cost are in a proportional relationship because the cost of zero pencils is $0 and
each additional pencil costs $3 more.
E. The number of pencils and the total cost are not in a proportional relationship because the cost of three pencils is $9, which is not proportional to the cost of one pencil.