Correct Answer: (a) Sand spit
Solution:A long narrow stretch of sand and/or shingle with one end attached to the mainland is called a sand spit. A sand spit is formed by the process of longshore drift, which is the movement of sediment along the coast. As waves approach the shore at an angle, they carry sand and sediment along the coast. When this sediment encounters a change in the shoreline, such as a river mouth or a change in the direction of the coastline, it can accumulate and form a sand spit.