Option 1: Valley - A valley is a low-lying area between hills or mountains, usually formed by a river or glacier. It is not specifically used to describe a tract of land between two confluent rivers in India.
Option 2: Plateau - A plateau is a flat or gently sloping elevated area. It is not specific to a tract of land between two confluent rivers in India.
Option 3: Doab - This is the correct term used in India for a tract of land lying between two confluent rivers. It is derived from the Persian word “do,” meaning two, and “ab,” meaning water. Doabs are commonly found in India, particularly in the northern region where rivers like the Ganges and Yamuna converge.
Option 4: None of these - This option is not correct as the term "doab" specifically refers to the land between two confluent rivers in India.