The correct answer is: a) Mizoram and Tripura.
Meghalaya was created on January 21, 1972, as the 16th state of India. It was formed from the two districts of East Khasi Hills and West Khasi Hills of Assam. The creation of Meghalaya was accompanied by the reorganization of other states in Northeast India, including Mizoram and Tripura.
Mizoram was created on February 20, 1987, as the 23rd state of India. It was formed from the Mizo Hills district of Assam. Tripura was created on January 21, 1972, as the 21st state of India. It was formed from the Tripura district of Assam.
The reorganization of other states in Northeast India was done to give more autonomy to the tribal people of the region. The creation of Meghalaya, Mizoram, and Tripura was a major step in this direction.
The other options are incorrect because they do not include Mizoram and Tripura. Assam and West Bengal are not located in Northeast India. Nagaland and Sikkim are located in Northeast India, but they were not reorganized as a result of the creation of Meghalaya. Arunachal Pradesh and Manipur are located in Northeast India, and they were reorganized as a result of the creation of Meghalaya, but they were not included in the list of states that were reorganized.