Explanation:

- Continental Shelf:

- This is the correct answer.

- The continental shelf is the extended perimeter of each continent, covered by relatively shallow seas.

- It gradually slopes and has depths of about 200 meters on average.

- Continental Slope:

- This area marks the transition between the continental shelf and the deep ocean floor.

- It is steeper compared to the shelf, with depths significantly increasing.

- Deep Sea Plains:

- These are large, flat areas on the ocean floor, known as abyssal plains.

- They lie at great depths, typically around 3,000 to 6,000 meters.

- Trenches:

- The deepest parts of the ocean.

- They are narrow and deep depressions in the sea floor.

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