The correct answer is B. Patna.
The 16th session of Bihari Students Conference was held in Patna on 26-27 December 1938. The conference was attended by over 10,000 students from all over Bihar. The main objective of the conference was to discuss the problems faced by the students of Bihar and to find solutions to these problems. The conference also passed a number of resolutions, including a resolution demanding the establishment of a separate university for Bihar.
The Bihari Students Conference was an important event in the history of Bihar. The conference helped to raise awareness of the problems faced by the students of Bihar and to bring about some positive changes in the education system of Bihar.
Option A is incorrect because Hazaribag is a city in Jharkhand, not Bihar.
Option C is incorrect because Ara is a city in Bihar, but the 16th session of Bihari Students Conference was not held there.
Option D is incorrect because Chhapra is a city in Bihar, but the 16th session of Bihari Students Conference was not held there.
Option E is incorrect because the 16th session of Bihari Students Conference was held in Patna.