Answer: D. No less than 50,000 pixels.
Answer analysis: When discussing the conditions that a conventional display screen must meet to work properly, we can analyze it from the basic composition and functional requirements of the display screen.
A. Power supply system: The display screen needs a stable power supply to work properly. Whether it is an LED display screen, an LCD display screen or other types of display screens, a power supply system is required to provide the necessary power. Therefore, the power supply system is the basis for the normal operation of the display screen.
B. Control system: The control system is responsible for receiving and processing signals from the outside, and controlling the light or color change of each pixel on the display screen, so as to present a complete image or video. Without the precise control of the control system, the display screen will not be able to display the content normally.
C. Playback system (or content playback system): Although the word "playback system" may not be an independent system directly corresponding to the display screen in the conventional context, we can understand it as the ability of the display screen to receive and display content (such as video, images, text, etc.). This is actually an important function of the display screen, because it enables the display screen to interact with the outside world and display valuable content. Therefore, in a broad sense, the playback system is necessary for the normal operation of the display screen.
D. No less than 50,000 pixels: This condition is not necessarily met by all conventional displays. The number of pixels of a display depends on its resolution and size. For example, a small display used in a specific scene may not need to reach 50,000 pixels. In addition, the number of pixels has no direct relationship with the normal operation of the display; even if the number of pixels is small, as long as the power supply, control and playback system of the display is normal, it can still work.
In summary, the condition that a conventional display must not meet to work properly is option D: "No less than 50,000 pixels". This condition is too specific and not universal, and it is not a standard that all displays must meet.