What is the length of India's coastline of India's mainland?

Explanation:

The length of the coast of  mainland India is 6100 km.

The length of the Indian coast, including the coasts of the Andaman and Nicobar Islands in the Bay of Bengal and the Lakshadweep Islands in the Arabian Sea, is 7517 km.

The coast of  mainland India borders the Arabian Sea to the west, the Bay of Bengal to the east, and the Indian Ocean to the south.

Final Answer:

Hence, the correct option is (D) i.e, About 6100 km.