The correct answer is: a) Regulate movement and protect tribal lands.
The Inner Line Permit system was introduced in the Mizo hills in 1873 to regulate the movement of people into the region and to protect the tribal lands from outside interference. The system required all non-tribal people to obtain a permit before entering the hills, and it also prohibited the sale of land to non-tribal people. The Inner Line Permit system was designed to preserve the traditional way of life of the Mizo people and to prevent them from being overwhelmed by the influx of outsiders.
Option b) is incorrect because the Inner Line Permit system was not introduced to suppress rebellions. The Mizo rebellion of 1895-1896 occurred after the Inner Line Permit system was already in place.
Option c) is incorrect because the Inner Line Permit system was not introduced to promote Christian missionary activities. The British government was generally opposed to Christian missionary activities in the Mizo hills, and it did not allow missionaries to enter the region without a permit.
Option d) is incorrect because the Inner Line Permit system was not introduced to facilitate trade with Burma. The British government was concerned that trade with Burma would lead to the influx of outsiders into the Mizo hills, and it did not want to encourage trade between the two regions.