Answer;
B. They cause waves to break offshore.
Explanation;
- Sand dunes are landforms that develop where there is an adequate supply of sand and where prevailing winds are strong enough for sand movement to occur.
- Sand dunes are a natural barrier to the destructive forces of wind and waves. They are first line of defense against coastal storms and beach erosion.
- They absorb the impact of storm surge and high waves, preventing or delaying flooding of inland areas and damage to inland structures.