The Tubes in Fluorescent Lamps Have a White Powder on Their

The tubes in fluorescent lamps have a white powder on their inner surfaces. This powder

A) slows down the white light produced by the gas atoms inside the tube so that less of that white light reflects as it passes through the walls of the tube.
B) conducts electricity from one electrode to the other and emits visible light as current passes through it.
C) absorbs ultraviolet light and uses the energy from that light to produce visible light.
D) scatters the white light produced by the gas atoms inside the tube so that it is both vertically and horizontally polarized and doesn't cause glare.