The correct answer is: C. both (a) and (b)
Tripura is a state in northeastern India. It is bordered by Bangladesh to the north, east, and west, and by Assam and Mizoram to the south. The capital of Tripura is Agartala.
Assam is a state in northeastern India. It is bordered by Bhutan to the north, Arunachal Pradesh to the northeast, Nagaland to the east, Manipur to the southeast, Mizoram to the south, Tripura to the southwest, Meghalaya to the west, and West Bengal to the northwest. The capital of Assam is Dispur.
Mizoram is a state in northeastern India. It is bordered by Bangladesh to the north, east, and west, and by Assam and Tripura to the south. The capital of Mizoram is Aizawl.
Bangladesh is a country in South Asia. It is bordered by India to the west, north, and east, and by Myanmar to the southeast. The capital of Bangladesh is Dhaka.