Why Correct: The Great Barrier Reef, the world's largest coral reef system, is located off the coast of Queensland, Australia.
Distractor Analysis: Austria is a landlocked European country with no coastline. Antigua is an island nation in the Caribbean. Andaman refers to the Andaman Islands, part of India in the Bay of Bengal; although coral reefs exist there, the Great Barrier Reef is specifically Australian.
Takeaway: The Great Barrier Reef is a World Heritage Site and the only living structure that can be seen from low Earth orbit. Locations of major natural wonders: Great Barrier Reef (Australia), Great Blue Hole (Belize), Great Rift Valley (East Africa).