Which of the following State has the lowest density of population as per the Census of 2011?"

1. A

   Himachal Pradesh

   Himachal Pradesh had a 2011 density of about 123 persons per sq km—low by all-India standards, but not the lowest in this list.

2. B

   Arunachal Pradesh

   Arunachal Pradesh recorded the lowest population density among Indian States in Census 2011 (17 persons per sq km). That is the official key.

3. C

   West Bengal

   West Bengal was among the densest large States in 2011 (about 1,028 per sq km), the opposite of ‘lowest’.

4. D

   Mizoram

   Mizoram’s 2011 density (about 52 per sq km) was low, yet still well above Arunachal Pradesh.

Summary. Official key is (b) Arunachal Pradesh. Census 2011 ranked it last among States for density; Bihar was among the highest. Mizoram and Himachal are sparse hill States but not the minimum. West Bengal is a high-density trap. Honour the stored letter (b).