Question

One of the rivers that originate in Nepal and floods the Northern Plains is ____________.
A. Mahanadi
B. Kosi
C. Yamuna
D. Indus

Answer 1

Hint: This River is also called “Sorrow of Bihar”. It got this title due to the fact that it causes large scale flooding every year, submerging agricultural land and devastating the rural economy.

Complete answer:
Kosi river (or Koshi River) has seven upper tributaries and because of it, also referred to as Saptakoshi (mainly in Nepal). Two tributaries originate from Tibet namely the Arun river and Sun Kosi. Another tributary, the Tamor River originates from the Kanchenjunga area in the east.
Along with draining the southern slopes of Nepal it also drains the northern slopes of the Himalayas in Tibet. The confluence of upper tributaries happens north of Chatra Gorge. This gorge is a canyon cut by Kosi river in the Mahabharata mountain range of Nepal.
This 720 km long river when a cross into Bihar, it branches into distributaries before joining the Ganga river near Kursela (Katihar district). Because of its nature of getting distributed after entering Bihar, the floodplain of this river includes a very large area of land. During the monsoon season, all these streams get flooded and eventually overflow, resulting in large scale flooding.
As observed in the last 200 years, this River has shifted its course many times from east to west by several kilometers. This unpredictable nature of the Kosi River is what makes it dangerous and it has caused suffering for millions of people, since historical times. It causes loss of agricultural produce, property, livestock, and much more.

Thus, option (B) is correct.

Note: According to legends, the name Kosi is derived from the Hindi word Kosna (to curse) because of the damage this river has done.