Kosi river is known as the Sorrow of Bihar. What is the real name of Kosi river?

Q. Kosi river is known as the Sorrow of Bihar. What is the real name of Kosi river?
Answer: Kaushiki
Notes: The real name of Kosi river is Kaushiki. Kosi origniates in the Himalayas and after that Seven streams flow in the eastern part of Nepal. The seven streams are: Sut Kosi, Bhotia Kosi, Tamba Kosi, Doodh Kosi, Likhu, Athasha and Tambar.