HELP !!!

Jamaal bounces on a trampoline. His height, as a function of time, is
modeled by y = -16x2 + 20x + 4.

Which statement best describes the function?

A. The function is linear.

B. Not enough information is given to decide.

C. The function is linear at some points and nonlinear at other points.

D. The function is nonlinear.