Identify the sealed glass vacuum tube containing an electron beam that is focused on a phosphor-coated glass screen when light is emitted.

Correct option is A

The correct answer is (a) Cathode ray tube.
 A cathode ray tube (CRT) is a sealed glass vacuum tube in which an electron beam is directed onto a phosphor-coated glass screen.
 When the electron beam strikes the phosphor coating, it emits light, creating images on the screen.
 CRTs were commonly used in older television sets and computer monitors before the advent of modern display technologies.
Information Booster:
Flat array tube:
 Not a standard display technology and does not describe any known common display type.
Light Emitting Diode (LED) tube:
 LED technology uses diodes that emit light when an electric current passes through them.
 Commonly used in modern display screens, lighting, and indicator lights.
Liquid Crystal Display (LCD) tube:
 LCD technology uses liquid crystals that modulate light when an electric current is applied.
 Widely used in modern monitors, televisions, and portable device screens.