Answer:
b) breakwater
Step-by-step explanation:
A breakwater is a structure built to protect a shoreline from the force of incoming waves.
It is typically made of rocks, concrete, or other materials. Breakwaters can be found along coastlines all over the world.
So, the answer is (b). breakwater

Let's see the other options:
- Barrier reefs are also structures that protect shorelines, but they are formed by living organisms, such as coral.
- Beaches are accumulations of sand and other sediments along shorelines.
- Tidal pools are small bodies of water that are separated from the ocean by sandbars or other barriers.