The correct answer is A. 64.434 million.
The total population of Bihar as per the 2011 census is 103,804,637. However, the reorganised State of Bihar came into existence on 15 November 2000, when the erstwhile State of Bihar was bifurcated into two new States, Bihar and Jharkhand. The population of the reorganised State of Bihar as per the 2011 census is 64,434,637.
Option B is incorrect because the total population of Bihar as per the 2011 census is 103,804,637.
Option C is incorrect because the total population of the reorganised State of Bihar as per the 2011 census is 64,434,637.
Option D is incorrect because the total population of the reorganised State of Bihar as per the 2011 census is 64,434,637.