Final answer:
When an LCD display is interfaced with 4-way multiplexing, it has four COM lines which are used to control the pixels and their colors by varying the voltage applied.
Step-by-step explanation:
An LCD display can be interfaced with a system using various methods, one such method being multiplexing. Specifically, when an LCD is interfaced with 4-way multiplexing, it implies that the LCD display is designed to share the display segments among four different common lines, typically referred to as COM lines. In this scenario, the number of COM lines would be four. These lines are part of the method used to control which pixels are lit on the display, dictating the image that is projected. By varying the voltage applied to these COM lines and corresponding segments, the LCD controls the passage of light through the red, blue, or green filters of each pixel, thus affecting the displayed image and its contrast.