Tamil Nadu has a long coastline of about:

The correct answer is (b). Tamil Nadu has a long coastline of about 1000 km. It is bordered by the Bay of Bengal to the east and the Arabian Sea to the west. The coastline of Tamil Nadu is a popular tourist destination, with many beaches, temples, and other historical sites.

Option (a) is incorrect because Tamil Nadu’s coastline is much longer than 500 km.

Option (c) is incorrect because Tamil Nadu’s coastline is not quite 1500 km long.

Option (d) is incorrect because Tamil Nadu’s coastline is not quite 2000 km long.