Correct Option: B

The Sivalik Hills is the outermost range of the Himalayas. Also known as Manak Parbat, it located in between the Great Plains and Lesser or Middle Himalayas. This range is about 2,400 km long enclosing an area that starts almost from the Indus and ends close to the Brahmaputra, with a gap of about 90 kilometres between the Teesta and Raidak rivers in Assam.