Which one should I choose?

Answer:
A
Step-by-step explanation:
The answer is A as the height starts at 36 and decreases by 9 inches vertically every 12 inches it goes down horizontally.
If you turn this into an equation, you get y = -(9/12)x+36.
Then, you simplify this to y = -(3/4)x+36, which is A.