Formed through longshore drift
a. sea stack
b. sandbar
c. spit
d. headland

Answer;

Sand Spit or Spit

Explanation;Long shore drift is the process that occurs when a sheet of water moves on and off the beach, in other words the swash and back swash, thus capturing and transporting sediment on the beach back out to the sea. Sandbar is normally formed when the sandspit stretches across a bay and connects the two sides. Headland is a high piece of land that extends out onto the sea. Sea stacks on the other hand results from the collapsing of the roof of the arch.