Julia is writing the equation shown in this graph. She writes it as x = 7.5y . What did she do wrong?

The first quadrant of a coordinate plane with Number of Hours on x axis and Earnings, in dollars, on the y axis. A straight line is graphed. The line passes through zero, zero and 5, thirty-seven point 5.
A
The equation is really x = 15y.

B
She needed to multiply x and y to get the equation xy = 7.5.

C
She reversed the variables x and y.

D
The constant of proportionality needs to be a fraction.