The correct answer is: B. 10.21%
Bihar is the third most populous state in India, with a population of 102,879,130 as of 2011. This accounts for 10.21% of the total population of India, which was 1,210,193,422 in 2011.
The other options are incorrect because they do not represent the percentage of Bihar’s population in the total population of India.
Option A: 9.33% is the percentage of Bihar’s population in the total population of India in 2001.
Option C: 16.44% is the percentage of Bihar’s population in the total population of India in 1991.
Option D: 8.04% is the percentage of Bihar’s population in the total population of India in 1981.