The correct answer is "there were already some groups fighting against the kingship and its protector, the British." The native State of Tripura became involved in the Freedom Movement early in the 20th century because there were already some groups within Tripura that were fighting against the kingship and its alliance with the British. These groups sought to challenge the authority of the kings and the influence of the British in the region. Their efforts were part of the broader freedom movement in India seeking independence from British colonial rule.