As per Census 2011, what is the rank of Bihar in terms of population density among all Indian states?

The correct answer is A. 1st.

Bihar is the most populous state in India, with a population of 104,099,192 as of 2011. It has a population density of 1,106 persons per square kilometer (2,860/sq mi), which is the highest among all Indian states.

The other options are incorrect.

Option B is incorrect because the third most populous state in India is Uttar Pradesh, with a population of 199,581,477 as of 2011.

Option C is incorrect because the fifth most populous state in India is Maharashtra, with a population of 112,374,333 as of 2011.

Option D is incorrect because the sixth most populous state in India is West Bengal, with a population of 91,347,736 as of 2011.