The correct answer is A) Bangalore Urban.
Bangalore Urban is the most populous district in Karnataka, with a population density of 3,132 persons per square kilometer. This is more than double the population density of the state as a whole, which is 1,406 persons per square kilometer.
Bangalore Urban is home to the city of Bangalore, which is the capital of Karnataka and the third most populous city in India. Bangalore is a major center of technology and innovation, and it attracts a large number of people from all over India.
The other options are incorrect because they are not as populous as Bangalore Urban. Dakshina Kannada has a population density of 1,022 persons per square kilometer, Belgaum has a population density of 396 persons per square kilometer, and Shimoga has a population density of 286 persons per square kilometer.