Question

What do you understand by the terms 'Doab'?
A. Where the delta of river begins
B. Where two or more rivers meet
C. Land between two separate river systems
D. Land between two tributaries of a river

Answer 1

Hint:Full forum of DOAB is Directory of Open Access Books. A word used in South Asia for the land tract between two confluent rivers is Doab. It's an interfluve-like item.

Complete answer:
A DOAB is a place where two small streams merge and result in the creation of a large river. The small streams may be a river's tributaries as well. Land means 'Doab' between two tributaries of a river.
Ganges-Yamuna Doab, Western and Southwestern Uttar Pradesh State of the Indo-Gangetic Plain Part, Northeastern India.
Located between the Ganges (Ganga) and Yamuna rivers, west of the Upper Ganges Plain, it has an area of around 23,360 square miles (60,500 square km).
The doabs are low-lying lands between the rivers that are immensely fertile because of the depositions carried by the waters of the rivers, making them suitable for agriculture.
The doabs also receive continuous irrigation water, making agricultural plots more suitable for these lands.

Hence, Option D Land between two tributaries of a river is the correct answer.

Note:The doab can be split into three sections: upper, middle, and lower.
The Upper Doab stretches from the north of Haridwar to the south of Aligarh. It has a gentle slope and a variety of streams are crisscrossed.
In the Middle Doab, secondary transverse slopes have formed on older floodplains.
In the Lower Doab, the topography flattens out where the streams of Sind, Betwa, and Ken run parallel to each other. The entire area geologically forms part of the alluvial Indo-Gangetic trough. The trees, which occur in patches, consist of acacia and teak.