Correct Answer: (d) Varanasi and Lalitpur
Solution:As per Census 2001, most densely populated (Population density/sq km.) districts of Uttar Pradesh are Varanasi (2045), Ghaziabad (2811), Lucknow (1443) and Bhadohi (1334). The district with the lowest population density are Lalitpur (194), Sonbhadra (218), Chitrakoot (249) and Hamirpur (247). According to Census 2011 (final data), most densely populated district of the state is Ghaziabad (3971) and district with lowest population density is Lalitpur (242).