Correct Option: D

Karnali or Ghaghara River is a perennial transboundary river originating on the Tibetan Plateau near Lake Mansarovar. It cuts through the Himalayas in Nepal and joins the Sarda River at Brahmaghat in India. Together they form the Ghaghra River, a major left bank tributary of the Ganges. With a length of 507 kilometres (315 mi) it is the largest river in Nepal.