Which of the following reason is responsible for the presence of a number of lagoons on Indian coasts?

The indented coasts in the Indian coastline

India has a vast coastline and the coast is very indented in some states. Due to this, a number of lagoons and lakes have formed. States like Kerala, Odisha, and West Bengal have vast surface water resources in these lagoons and lakes. Although water is generally brackish in these water bodies, it is used for fishing and irrigating certain varieties of paddy crops, coconut, etc.