India’s second longest railway bridge i.e. Nehru Setu or Dehri-on-Son is constructed on which river in Bihar?

The correct answer is option B. Sone.

Nehru Setu or Dehri-on-Son is a railway bridge over the Son River in Bihar, India. It is the second longest railway bridge in India, after the Howrah Bridge. The bridge was built in 1959 and is 1,500 meters long. It connects the towns of Dehri-on-Son and Sonpur.

The other options are incorrect. The Ganga is a river in northern India and Bangladesh. The Ghaghara is a river in northern India and Nepal. The Gandak is a river in northern India and Nepal.