The correct answer is C.
Screen saver. The screen is filled with animated objects when the computer is
kept in idle and inactive for a fixed period of time. The time when screen
savers are triggered can be set in the control panel of the computer. The initial
use of the screen saver was to prevent the heating of the monitors, which was
then cathode ray tubes (CRT), due to steady and fixed display. Now, a screen
saver can protect users with password prompts when a computer is left
unattended for a certain time.
