Final answer:
Docking UI elements to the left side of the screen ensures that they remain consistent and functional across various devices, providing a stable user interface regardless of screen size or resolution.
Step-by-step explanation:
The most relevant reason for docking UI elements to the side of the screen would be to ensure consistency and functionality across various devices. Option 4 states, "Lee can be sure that the UI elements remain connected to the left side of the screen no matter what device players use." This implies that docking is being used to keep the interface stable and accessible, regardless of the screen size or resolution of the device. It helps in maintaining the layout and usability of the UI when the game is played on different platforms, which is essential in providing a good user experience.