A Model Rocket Is Launched from the Roof of a Building

A model rocket is launched from the roof of a building. For height $h$ , in meters, and time $t$ , in seconds, after the rocket is launched, the height of the rocket above the ground is given by $h=f(t) =-4.9 t^{2}+43 t+21$ . Interpret the domain of the graph of $f(t)$ .

A) The time it takes for the rocket to hit the ground
B) The rocket's initial height
C) The heights the rocket reaches
D) The time the rocket is in the air
E) The maximum height obtained by the rocket.