Correct Answer: (a) Jaipur, Jodhpur, Alwar, Nagaur
Solution:According to the Census 2011, the descending order of Rajasthan largest populated district is - Jaipur (6,626,178), Jodhpur (3,687,165), Alwar (3,674,179), Nagaur (3,307,743) and Udaipur (3,068,420).