The correct answer is: a) Hydropower.
Jammu and Kashmir has significant potential for the development of hydropower. The state has an estimated hydropower potential of 20,000 MW, of which only about 3,000 MW has been developed so far. The main rivers in Jammu and Kashmir are the Chenab, Jhelum, and Indus, all of which have the potential for hydropower development.
Coal mining is not a major industry in Jammu and Kashmir. The state has only a small amount of coal reserves, which are of low quality.
Oil extraction is also not a major industry in Jammu and Kashmir. The state has no known oil reserves.
Shipbuilding is not a major industry in Jammu and Kashmir. The state has no major ports or shipyards.
In conclusion, the correct answer is: a) Hydropower.