The correct answer is: All of the above.
The British were particularly cautious in their dealings with the Mizos after 1857 due to a number of factors. First, they feared that a similar uprising could occur in the hills. The Indian Rebellion of 1857, also known as the Sepoy Mutiny, was a major uprising against British rule in India. It began on May 10, 1857, when a group of Indian soldiers in Meerut refused to use new cartridges that they believed were greased with cow or pig fat, which was offensive to both Hindus and Muslims. The rebellion quickly spread to other parts of India, and by the end of 1857, the British had lost control of much of the country. The rebellion was eventually suppressed, but it left a deep scar on the British psyche. The British were determined to prevent any further uprisings, and they were particularly wary of the Mizos, who were a fierce and independent people.
Second, the British had reduced military manpower after the Indian Rebellion of 1857. Many British soldiers had been killed or wounded in the rebellion, and the British government was reluctant to send more troops to India. This left the British with fewer resources to deal with the Mizos, who were a constant threat to British rule in the hills.
Third, the British were shifting their focus towards internal security. After the Indian Rebellion of 1857, the British government was determined to consolidate its control over India. This meant that they were less willing to engage in costly military campaigns in the hills. Instead, they preferred to negotiate with the Mizos and try to keep them under control through diplomacy.
In conclusion, the British were particularly cautious in their dealings with the Mizos after 1857 due to a number of factors, including fear of a similar uprising in the hills, reduced military manpower, and a shifting focus towards internal security.