Correct Answer: Option B) 1 & 3
The Kosi is referred to as the 'Sorrow of Bihar' - True
The Kosi River is indeed called the "Sorrow of Bihar" due to its frequent devastating floods that affect large parts of Bihar. The river frequently changes its course and causes widespread destruction in the state.
The Kosi Project is a collaboration between India and Bangladesh - False
The Kosi Project is actually a collaboration between India and Nepal, not Bangladesh. The Kosi Barrage was built under an agreement between India and Nepal. The Ganges projects involve Bangladesh, but not the Kosi projects.
The main tributary of the Kosi, Arun, originates north of Mount Everest - True
The Arun River, which is one of the main tributaries of the Kosi, does originate in Tibet (China), north of Mount Everest in the Himalayan region. It flows southward through Nepal before joining the Kosi river system.