The correct option is C Both statments are true and statement 2 is the correct explanation of statement 1.
The Cholas built a robust naval fleet, and they were able to wrest control over the Cholamandel and Malabar coasts, the Bay of Bengal and large parts of the Indian Ocean. Their powerful navy also enabled them to make conquests in Malaya, various islands within the Indian Ocean and carry on trade with Ceylon, East Indies and Persia.