60 POINTS!!! CAN SOMEBODY PLEASE HELP ME!! I DONT WANT TO FAIL THIS!

3. A rocket is launched vertically from the ground with an initial velocity of 64 .
(a) Write a quadratic function that shows the height, in feet, of the rocket t seconds after it was launched.
(b) Graph on the coordinate plane.

(c) Use your graph from Part 3(b) to determine the rocket’s maximum height, the amount of time it took to reach its maximum height, and the amount of time it was in the air.
Answer:

(A): The equation is h(t)= -16t^2 + 64t

(B): The vertex points are (2,64) and the t intercepts are 0 and 4

(C): I dont know c!! i need help!

PLEASE EXPLAIN WELL!!!