Which of the following can be an example of accretion?

Accretion refers to the gradual accumulation of soil and sediment in a particular area, which can lead to an increase in land area. The process often involves natural forces such as rivers depositing soil along their banks or deltas. In this context, the first choice, which describes soil deposited by a river over time, perfectly exemplifies accretion.

Rivers carry sediments and, as they slow down upon reaching still bodies of water or the riverbank, they often drop or deposit these sediments. Over time, this deposited material builds up, creating new land or extending the existing land. This natural process contributes to the formation of ecosystems and can change the landscape significantly.

The other options, while related to land and water interactions, do not illustrate the concept of accretion. Coastal erosion involves the loss of land rather than its gain, land reclaimed from the ocean typically refers to land that has been artificially raised or created, and the creation of sand dunes involves the movement and accumulation of sand due to wind, which is a different process from the accumulation of sediment by water.