The correct option is D Ludhiana
The population density is the ratio between the land area and the people living
over it. It is the number of people per unit of area, usually quoted ‘population per
square kilometer’.The density of population in Punjab has increased from 484 persons per square
kilometer in 2001 to 551 persons per square kilometer in 2011. In Punjab, Ludhiana (population density of 978 persons per square kilometer)
is the most populated district.