The correct answer is: A. Patna.
The first Congress Session in Bihar was held in Patna on December 26-27, 1912. The session was presided over by Lala Lajpat Rai. The main objective of the session was to discuss the political situation in India and to formulate a strategy for the future. The session was attended by over 2,000 delegates from all over India.
The session was a major success and it helped to strengthen the Congress movement in Bihar. It also helped to raise awareness of the political situation in India and to mobilize support for the Congress movement.
The other options are incorrect because they are not the places where the first Congress Session in Bihar was held.
Option B: Gaya is a city in Bihar. It is located on the banks of the Phalgu River. Gaya is a major pilgrimage site for Hindus and Buddhists.
Option C: Muzaffarpur is a city in Bihar. It is located on the banks of the Gandak River. Muzaffarpur is a major educational and commercial center.
Option D: Darbhanga is a city in Bihar. It is located on the banks of the Kosi River. Darbhanga is a major cultural and religious center.
Option E: None of the above.