Which of the following is a low island found in tropical oceans with brackish water?

Correct option is A

Introduction
An Atoll is a ring-shaped coral reef, island, or series of islets that nearly or entirely encloses a body of water called a lagoon.
· Location: They are typically found in tropical oceans.
· Elevation: The coral islands (islets) on the reef ring are naturally low-lying.
· Brackish Water: The enclosed lagoon's water is often brackish (a mix of salt and fresh water) due to rainfall and limited exchange with the open sea.
Information Booster
· Structure: A ring-shaped coral reef enclosing a lagoon.
· Formation: They are formed when a fringing or barrier reef continues to grow upward around a volcanic island that has subsided and disappeared below sea level.
· Water Type: The enclosed lagoon contains brackish water, which is a mixture of saltwater and freshwater.
· Height: The islands formed on the reef are very low-lying.
· Ecosystem: Atolls support a unique marine and terrestrial ecosystem adapted to the shallow and brackish environment.
Additional Points
· Oceanic Ridge: A continuous, underwater mountain range in the ocean basins, not a low island with brackish water.
· Guyot: A flat-topped seamount (underwater mountain); it is entirely submerged, not a low island.
· Seamount: An underwater mountain rising from the ocean floor that does not reach the water's surface; it is entirely submerged, not an island.