The correct answer is C. Patna.
Patna is the capital and most populous city of the Indian state of Bihar. As of 2011, it is the 19th most populous city in India with an estimated population of 1.68 million in the urban agglomeration and 1.07 million in the municipal corporation area.
Patna is one of the oldest continuously inhabited cities in the world. It was founded in the 6th century BCE by the king of the Magadha Empire, Bimbisara. Patna was the capital of the Mauryan Empire, the Gupta Empire, and the Pala Empire.
Patna is a major center for education, healthcare, and culture. It is home to several universities, including the Patna University, the Indian Institute of Technology Patna, and the National Institute of Technology Patna. Patna is also home to several hospitals, including the Patna Medical College and Hospital, the All India Institute of Medical Sciences Patna, and the Indira Gandhi Institute of Medical Sciences.
Patna is a major tourist destination. The city is home to several historical monuments, including the Patna Fort, the Golghar, and the Kumhrar archaeological site. Patna is also home to several temples, including the Mahabodhi Temple, the Vishnupad Temple, and the Patna Sahib Gurudwara.
The urban population of Patna as per Census 2011 is 1.07 million. This is the highest among all the districts of Bihar. The urban population of Sheohar, Arwal, and Bhagalpur is 276,000, 243,000, and 475,000 respectively.