The table shows the linear relationship between the total amount Mrs. Jacobs will be charged for a skating party and the number of children attending.

Number of children ​Total amount charged
5 $82.50
8 $105.00
12 $135.00
15 $157.50​​

Which equation best represents y, the total amount in dollars Mrs. Jacobs will be charged for x number of children attending the skating party?

a. y=16.5x
b. y=7.5x+45
c. y=22.5x+82.5
d. y=45x+7.5