The correct option is D China
In 1914 Shimla convention, the land boundary demarcated by Chief British negotiator Sir Henry McMohan between Tibet frontier and Assam is known as McMohan line. The line runs from the eastern border of Bhutan along the Himalayas until it reaches the bend of Brahmaputra river into the Assam valley. Delegates of Chinese government attended the convention but refused to sign the principal agreement on the grounds that Tibet was subordinate to China and didn't have powers to make treaties. China have maintained position till the present day that its territory extends southwards to the base of Himalayan foothills.