Question

an archipelago is a group of islands close together in a large body of water.
select the archipelago.

Explanation:

An archipelago is defined as a group of islands close together in a large body of water. The third image shows multiple islands (landmasses) close to each other in a body of water, while the first shows coastal landforms and the second shows a coastal or river - related landform without multiple islands. So the third image represents an archipelago.

Answer:

The third image (the one with multiple separate but close - together landmasses in water) is the archipelago.