The correct answer is option 2: 2, 3 and 4 only.

Let`s dissect each option to better understand why.

Option 1 states that mangrove plants require an appropriate mix of saline water and freshwater. This statement is correct. Mangrove plants are adapted to survive in the unique environment of coastal areas, where they need both saline and freshwater to grow.

Option 2 states that mangrove plants require mudflats to enable them to grow and develop. This statement is also correct. Mudflats provide a stable substrate for the roots of mangrove plants and allow them to anchor themselves in the soil.

Option 3 states that mangrove plants are found in the inter-tidal zones of sheltered coasts. This statement is correct. Mangrove plants typically grow in inter-tidal zones, which are the areas between high and low tide. They thrive in sheltered coasts where they are protected from strong waves and currents.

Option 4 states that mangrove vegetation has been reported in all the coastal states, including Andaman and Nicobar Islands. This is also correct. Mangrove forests can be found in various coastal areas around the world, including all the coastal states of India, as well as the Andaman and Nicobar Islands.

Therefore,