A) Refers to the blanking signals which occur at the end of each field.

b) The time during which the electron beams of an output device are turned off and positioned to the upper left edge of the display.

c) A video synchronising signal that defines the border or black area at the top and bottom of the display and, in a CRT, hides (blanks out) the electron beam’s retrace path from the bottom to the top of the display.