The correct answer is B. CRT and LCD.
A CRT monitor is a cathode ray tube monitor, which is a type of display device that uses a cathode ray tube to generate an image. A CRT monitor consists of a glass tube that contains an electron gun, a phosphor screen, and a yoke. The electron gun emits a beam of electrons, which is focused onto the phosphor screen. The phosphor screen emits light when it is struck by the electron beam. The yoke controls the deflection of the electron beam, which allows the image to be displayed on the screen.
An LCD monitor is a liquid crystal display monitor, which is a type of display device that uses liquid crystals to generate an image. An LCD monitor consists of a glass panel that contains a liquid crystal layer, a polarizing filter, and a backlight. The liquid crystal layer is sandwiched between the polarizing filter and the backlight. The liquid crystals are arranged in a way that allows light to pass through them when they are energized by an electric current. The polarizing filter allows only light that is polarized in a certain direction to pass through it. The backlight provides the light that is needed to illuminate the image on the screen.
DVD and VCD are both types of optical disc storage formats. A DVD is a digital versatile disc, which is a type of optical disc that can store up to 4.7 GB of data. A VCD is a video compact disc, which is a type of optical disc that can store up to 74 minutes of video.
E is not a correct answer because it does not list two types of monitors.