Aball is dropped from the top of a building that is 1,000 feet high. its height, in feet, as a function of the time, x, in seconds, after the ball was dropped, is given by the following equation, f(x) = 1,000 - 16x2. which set of numbers is appropriate as the domain for this function? a: natural numbers b: positive real numbers c: positive integers d: positive rational numbers