The correct answer is (c) Sonbhadra.
Sonbhadra is the largest district in Uttar Pradesh, India, with an area of 7,429 square kilometers (2,868 sq mi). It is located in the southeastern part of the state, bordering Jharkhand to the south and east, Chhattisgarh to the southeast, Madhya Pradesh to the south, and Mirzapur district to the west and north. The district is named after the Son River, which flows through it.
Sonbhadra was formed in 1994 by carving out parts of Mirzapur and Chandauli districts. The district is divided into six tehsils: Robertsganj, Duddhi, Obra, Pipraich, Garhwa, and Sonbhadra. The headquarters of the district is at Robertsganj.
Sonbhadra is a predominantly rural district with a population of 1,742,476 (2011 census). The district is home to a number of tribal groups, including the Gonds, the Baiga, and the Korku. The main languages spoken in the district are Hindi, Bhojpuri, and Awadhi.
The economy of Sonbhadra is based on agriculture, forestry, and mining. The main crops grown in the district are rice, wheat, sugarcane, and maize. The district is also home to a number of mineral deposits, including coal, iron ore, and bauxite.
Sonbhadra is a beautiful and scenic district with a rich history and culture. The district is home to a number of historical monuments, including the ruins of the ancient city of Sonpur. The district is also home to a number of wildlife sanctuaries, including the Son Gharial Sanctuary and the Dudhwa National Park.