Hari Singh, who was the leader of Jammu and Kashmir, was a Hindu. Once India became independent from Britain, he was given a choice. He could choose where to go and he chose to join India since most of the people there were also Hindu.
C. The ruler's religion is different from the majority religion of his country.
Although Hari Sign was a Hindu, the majority of Jammy and Kashmir were not and since they suspected that Hari could choose India, the tribes of Pakistan plotted an invasion that forced Singh to ask for help from India.
C. Hari Singh decided to join India due to his religious background.