Which of the following situations does not represent a proportional relationship? *

a. Emilia earns $8.75 an hour and 10% commission on any new memberships she sells.
b. Tatum is flying a remote-controlled airplane at a speed of 18 miles per hour.
c. Phoebe is at a baseball game where they sell all drinks for $1.75 each.
d. All of the above are proportional.