Explanation:

- The features caves, arches, stacks, and stumps form along coastlines due to the action of waves eroding rock, not rivers or limestone solution processes.

- Option 1: River – These mainly form features like deltas, meanders, and oxbow lakes.

- Option 2: Wave – ( Correct Answer) Wave erosion creates coastal landforms like caves (hollowed in cliffs), arches (when caves break through), stacks (isolated columns), and stumps (remnants of collapsed stacks).

- Option 3: Limestone – Forms features like stalactites, stalagmites (caves, but different processes), and limestone pavements through chemical weathering, not waves.

- Option 4: Wind – Creates features like sand dunes and yardangs, not caves, arches, or stacks.