The correct answer is: a) Ludhiana.
Ludhiana is the largest city in Punjab, India, with a population of 3.1 million as of 2020. It is the industrial capital of Punjab and is known for its manufacturing of hosiery, bicycles, and machinery. Ludhiana is also a major educational center, with several universities and colleges located in the city.
Amritsar is the second largest city in Punjab, with a population of 2.1 million as of 2020. It is a holy city for Sikhs and is home to the Golden Temple, one of the most important Sikh shrines. Amritsar is also a major tourist destination, with several historical and cultural sites located in the city.
Jalandhar is the third largest city in Punjab, with a population of 1.7 million as of 2020. It is a major commercial and educational center and is home to several universities and colleges. Jalandhar is also a major transportation hub, with a railway station and an airport located in the city.
Patiala is the fourth largest city in Punjab, with a population of 1.1 million as of 2020. It is the former capital of the princely state of Patiala and is home to several historical and cultural sites. Patiala is also a major educational center, with several universities and colleges located in the city.