Had to look for the options and here is my answer. The reason why the ruler of Jammu and Kashmir doubted to join Pakistan or India is that he is afraid of invasions by both countries. Jammu and Kashmir is actually a princely state in the British Empire of India. Hope this answer helps.
The ruler's religion from the majority religion of his country.
Explanation:
As undoubtedly the Muslim dominated areas goes to Pakistan and majority of the religion there is Islam thus Jammu and Kashmir ruler heisted to join the Pakistan or India as it was different from his religion and at the time of the war he had either the option to join or remain independent which could not be possible, later the agreement was taken in favor of India.
