Which situation can be modeled by the equation y = mx + b?

Question

A.
The number of members (y) at an art club doubles every year (x).
B.
The time (y) it takes to climb up 160 steps depends on the number of steps climbed per minute (x).
C.
The monthly fee (y) for a tennis club that charges $15 per lesson depends on the number of lessons taken (x).
D.
The cost (y) of painting a square wall at a rate of $2 per square foot depends on the side length (x) of the square wall.

Answer 1

C. The monthly fee (y) for a tennis club that charges $15 per lesson depends on the number of lessons taken (x).