The odd one out is B, Kohima. The other three options are all states in India, while Kohima is the capital of Nagaland, a state in India.
Manipur is a state in northeastern India. It is bordered by Nagaland to the north, Assam to the east, Mizoram to the south, and Tripura to the southwest. The state has a population of over 2.8 million people and a land area of 22,327 square kilometers. The capital of Manipur is Imphal.
Sikkim is a state in northeastern India. It is bordered by Bhutan to the north, China to the east, Nepal to the west, and West Bengal to the south. The state has a population of over 610,000 people and a land area of 7,096 square kilometers. The capital of Sikkim is Gangtok.
Mizoram is a state in northeastern India. It is bordered by Assam to the north, Tripura to the west, Bangladesh to the south, and Myanmar to the east. The state has a population of over 1.1 million people and a land area of 22,086 square kilometers. The capital of Mizoram is Aizawl.