Which is the longest tributary of the river Ganga?

Correct option is B

• Other important tributaries of the Ganga include the Ghaghara, Kosi, and Gandak.
  

• The Yamuna River is a major river in India that flows through the Himalayas, Delhi, and Uttar Pradesh.

• The confluence of the Yamuna and Ganga at Prayagraj is known as the Sangam, a sacred site for Hindus.

•  Kosi – Originates from the Himalayas in Tibet (north of Mount Everest).
  
•  Gandak – Originates from the Nepal Himalayas near Tibet.
  
•  Ghaghara – Originates from the Mapchachungo Glacier in Tibet.