Final answer:
The level of database information which cannot be removed from the ECDIS display and consists of information which is required at all times in all geographic areas and under all circumstances is the display base information.
Step-by-step explanation:
The correct answer is D) display base information. Display base information refers to the level of database information that cannot be removed from the ECDIS (Electronic Chart Display and Information System) display. It consists of information that is required at all times, in all geographic areas, and under all circumstances. This information includes essential elements such as the ship's position, heading, velocity, and graphical presentation of the nautical chart.