I'll pick brainiest, pls help, also pls do not answer if you're going to tell me to download the work. The graph below shows the height of Cindy's model rocket during the course of its flight.
Flight of Cindy's Rocket

Height (in feet)
y
22
20
18
16
14
12
10
6
4.
2.
x 0 1 2 3 4 5 6 7 8 9
Time (in seconds)
Which of these equations can be used to find the height of the rocket at any time during its flight?
A. y = 9x
B. y = x^2 - 81
C. y = -x^2 + 9x
D. y = 9 - 9x^2.