Which of the following have coral reefs? 1. Andaman and Nicobar Islands 2. Gulf of Kachchh 3. Gulf of Mannar 4. Sunderbans Select the correct answer using the code given below.

Coral reefs are vibrant marine ecosystems that thrive in warm, clear, shallow, and saline waters. India is home to several important coral reef regions: **Andaman and Nicobar Islands**: These islands are well-known for their extensive, diverse, and pristine coral reefs, which are part of the Indo-Pacific coral triangle. They host fringing, barrier, and atoll reefs. **Gulf of Kachchh (Kutch)**: Located on the west coast of India, the Gulf of Kachchh is notable for having India's northernmost coral reefs, primarily fringing reefs. It's an important marine national park and sanctuary. **Gulf of Mannar**: Situated off the southeastern coast of India, between India and Sri Lanka, the Gulf of Mannar is a significant coral reef area and is designated as a Marine Biosphere Reserve, known for its rich marine biodiversity. **Sunderbans**: The Sunderbans, a large mangrove forest shared by India and Bangladesh, is known for its unique mangrove ecosystem. However, it does not typically host coral reefs. The conditions in the Sunderbans (high sediment load from riverine discharges, brackish water, and high turbidity) are generally unsuitable for the growth of most coral species, which require clear, saline water. Therefore, coral reefs are found in Andaman and Nicobar Islands, Gulf of Kachchh, and Gulf of Mannar.