Answer:
b. sediment trapping
A wetland is a distinct ecosystem that can be found in a region where deep surface of land is occupied with water either permanently or seasonally. The water gets deposited in the wetland comes from rain, melting of glaciers, irrigation of the agricultural land, river, lakes and ponds.
The water enters the wetland takes along with it minerals and sediments of the land surface due to surface runoff. These mineral particles gets deposited in the bed or floor of the wetland. Hence, the erosion of the minerals by wind or water is prevented by this sedimentation process.
Therefore, sediment trapping is a correct option which helps in the reduction of the erosion.
