The correct answer is (b).
The population of the four districts of Uttar Pradesh (UP) as per the 2011 Census is as follows:
- Lucknow: 2,811,105
- Allahabad: 2,117,467
- Ghaziabad: 1,997,528
- Moradabad: 1,801,832
Therefore, the correct sequence of the districts in descending order of population is:
- Lucknow
- Allahabad
- Ghaziabad
- Moradabad
Option (a) is incorrect because Moradabad is ranked higher than Allahabad in terms of population.
Option (c) is incorrect because Moradabad is ranked higher than Ghaziabad in terms of population.
Option (d) is incorrect because Allahabad is ranked higher than Ghaziabad in terms of population.