The correct answer is: A. West Champaran.
The Kosi Canal is the largest canal in Bihar. It is a major irrigation canal in India, which is part of the Kosi Project. The canal is 250 kilometers long and irrigates an area of 1.2 million hectares. The canal is located in the districts of West Champaran, East Champaran, Sitamarhi, Muzaffarpur, Darbhanga, and Samastipur.
The Kosi Canal was constructed in the early 1950s to provide irrigation to the drought-prone areas of Bihar. The canal has been a major success in increasing agricultural production in the region. The canal has also helped to improve the water supply for drinking and domestic purposes.
The Kosi Canal is a major source of employment for the people of Bihar. The canal provides employment to thousands of people in the construction, maintenance, and operation of the canal. The canal also provides employment to farmers who cultivate the land that is irrigated by the canal.
The Kosi Canal is a major asset for the state of Bihar. The canal has helped to improve the lives of millions of people in the region. The canal has also helped to boost the economy of Bihar.
The other options are incorrect because they are not the districts where the Kosi Canal is located.