The correct option is B Sagauli
Treaty of Sagauli was an agreement between the Gurkha chiefs of Nepal and the British Indian government that ended the Anglo-Nepalese (Gurkha) War (1814–16). As per the treaty, Nepal renounced all claim to the disputed Tarai, or lowland country, and ceded its conquests west of the Kali River and extending to the Sutlej River.