The correct answer is: c) 1000 km.
Tamil Nadu has a coastline of approximately 1000 km. It is the longest coastline of any state in India. The coastline of Tamil Nadu is a major tourist attraction, with many beaches and resorts. The coastline is also important for fishing and other marine industries.
Option a) is incorrect because it is too short. The coastline of Tamil Nadu is much longer than 500 km.
Option b) is incorrect because it is too short. The coastline of Tamil Nadu is much longer than 750 km.
Option d) is incorrect because it is too long. The coastline of Tamil Nadu is not as long as 1300 km.