Tamil Nadu has a long coastline of about:

The correct answer is: c) 1,500 km.

Tamil Nadu has a long coastline of about 1,500 km. It is bordered by the Bay of Bengal to the east and the Arabian Sea to the west. The state has a number of important ports, including Chennai, Tuticorin, and Madurai. The coastline is also home to a number of popular tourist destinations, including Kovalam, Mahabalipuram, and Kanyakumari.

Option a) is incorrect because Tamil Nadu’s coastline is actually about 1,500 km long, not 500 km.

Option b) is incorrect because Tamil Nadu’s coastline is actually about 1,500 km long, not 1,000 km.

Option d) is incorrect because Tamil Nadu’s coastline is actually about 1,500 km long, not 2,000 km.