he 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 it does not increase proportionally with the number of pencils.
B.
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.
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 increases with the number of pencils.

B.

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.