The correct option is B It has its own Constitution.
Under Part XXI of the Constitution of India, which deals with "Temporary, Transitional and Special provisions", the State of Jammu and Kashmir has been accorded special status under Article 370. Jammu and Kashmir is the only state in India which has a Constitution of its own. The Constitution of J&K was enacted by a separate Constituent Assembly set up by the State and it came into force on 26th January, 1957.