Coral reefs are underwater structures made of calcium carbonate secreted by corals. They are home to a diverse range of marine organisms and are considered one of the most productive and diverse ecosystems on the planet.

The Andaman and Nicobar Islands, Gulf of Kachchh, and Gulf of Mannar are all regions in India that have coral reefs. The Sunderbans, on the other hand, is a mangrove forest ecosystem and does not have coral reefs. Therefore, the correct answer is option 1, i.e., Andaman and Nicobar Islands, Gulf of Kachchh, and Gulf of Mannar.