The Imphal Valley is the central region of Manipur. It is a fertile valley surrounded by hills. The valley is home to the capital city of Imphal, as well as many other towns and villages. The Imphal Valley is a major agricultural region, and is also home to a number of industries.
The Barak Valley is a valley in the northeastern Indian state of Assam. It is located in the Barak River basin, and is bounded by the Manipur Hills to the north, the Lushai Hills to the south, and the Cachar Hills to the east. The Barak Valley is a major agricultural region, and is also home to a number of industries.
The Brahmaputra Valley is a valley in the northeastern Indian state of Assam. It is located in the Brahmaputra River basin, and is bounded by the Himalayas to the north, the Garo Hills to the south, and the Meghalaya Plateau to the west. The Brahmaputra Valley is a major agricultural region, and is also home to a number of industries.
The Teesta Valley is a valley in the northeastern Indian state of Sikkim. It is located in the Teesta River basin, and is bounded by the Himalayas to the north, the Singalila Range to the south, and the Mahabharat Range to the west. The Teesta Valley is a major agricultural region, and is also home to a number of industries.
Therefore, the correct answer to the question “Which river valley forms the central region of Manipur?” is Imphal Valley.