A stone dropped from the roof of a single-story building to the surface of the earth:

A.
falls because of the natural tendency of all objects to rest on the surface of the earth.

B.
reaches a maximum speed quite soon after release and then falls at a constant speed thereafter.

C.
speeds up as it falls because the gravitational attraction gets considerably stronger as the stone gets closer to the earth.

D.
speeds up because of an almost constant force of gravity acting upon it.

E.
falls because of the combined effects of the force of gravity pushing it downward and the force of the air pushing it downward.