What ecological service do the wetland provide?

They improve water quality, prevent soil erosion and land mass loss, protect coastlines, store away carbon, and provide habitats for a wide range of diverse plant and animal communities.

Explanation:

Wetlands are regions or areas of or periodically water-covered soil. These are classified as swamps, marshes, bogs, fens and shallow water. Others, that contain partially decomposed organic matter are known as peatlands.

These are diverse and essential regions found across several biospheres. They improve water quality, prevent soil erosion and land mass loss, protect coastlines, store away carbon, and provide habitats for a wide range of diverse plant and animal communities. Additionally, wetlands remove excess nutrients from runoff, preventing pollution of waterways.

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.