The correct answer is: b) Kosi River.
The Kosi Barrage is a major irrigation and flood control project located in Bihar on the Kosi River. It was constructed in 1954 to control floods and provide irrigation to the surrounding area. The barrage is 5,600 feet long and 100 feet high. It has 56 gates, each of which is 100 feet wide. The barrage has been effective in controlling floods, but it has also had some negative environmental impacts. For example, it has caused the siltation of the riverbed and the loss of wetlands.
The other options are incorrect. The Ganga River is located in Uttar Pradesh, Uttarakhand, Bihar, Jharkhand, and West Bengal. The Gandak River is located in Nepal and India. The Son River is located in Madhya Pradesh, Chhattisgarh, Jharkhand, and Bihar.