The correct answer is b) 580 km.
Kerala has a coastline of approximately 580 km. It is the longest coastline of any state in India. The coastline of Kerala is characterized by its beautiful beaches, backwaters, and lagoons. The beaches of Kerala are some of the most popular tourist destinations in India. The backwaters of Kerala are a unique ecosystem that is home to a variety of wildlife. The lagoons of Kerala are also a popular tourist destination.
Option a) 200 km is incorrect because the coastline of Kerala is much longer than 200 km.
Option c) 850 km is incorrect because the coastline of Kerala is shorter than 850 km.
Option d) 1200 km is incorrect because the coastline of Kerala is much shorter than 1200 km.