A local gym charges a one-time enrollment fee to join and a monthly charge. The total cost is modeled by the function y = 15x + 12. Which statement correctly interprets the function in context?
A. x is the cost and y is the number of months someone is a member of the gym; $15 is the enrollment fee and $12 is the monthly fee.
B. y is the cost and x is the number of months someone is a member of the gym; $12 is the enrollment fee and $15 is the monthly fee.
C. x is the cost and y is the number of months someone is a member of the gym; $12 is the enrollment fee and $15 is the monthly fee.
D. y is the cost and x is the number of months someone is a member of the gym; $15 is the enrollment fee and $12 is the monthly fee.