The coral reef, which is circular or elliptical in shape and encloses a lagoon, is called

Based on the provided geographical classifications, coral reefs are primarily categorized into fringing reefs, barrier reefs, and atolls. An atoll is specifically defined as a circular, semi-circular, or elliptical reef that arises from subsiding sea floor platforms [5]. These formations typically enclose a central body of water known as a lagoon, which may or may not contain a central island [4]. While barrier reefs also feature lagoons, they are linear structures running parallel to coastlines rather than circular rings [3]. The term 'Anatoli' in the options appears to be a phonetic or typographical variation of 'Atoll' (often referred to as 'Atoll' or 'Atollon' in various contexts), as it is the only term corresponding to the circular morphology described. Fringing reefs are contiguous with the shore, and coral dunes are not a standard classification of reef structures [5].

Sources

1. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 17: Major Landforms and Cycle of Erosion > Atolls > p. 222
2. [5] https://oceanservice.noaa.gov/facts/threecorals.html
3. [3] Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 11: Islands and Coral Reefs > Types of Goral Reef > p. 100
4. [4] CONTEMPORARY INDIA-I ,Geography, Class IX . NCERT(Revised ed 2025) > Chapter 2: Physical Features of India > Corals > p. 14