The correct answer is (b), Hamirpur.
According to the 2011 Census, the population of Hamirpur district was 1,882,723, of which 1,677,584 (89.8%) lived in rural areas and 205,139 (10.2%) lived in urban areas.
The other options are incorrect because the percentage of people living in rural areas is lower in those districts. For example, in Allahabad district, 84.2% of the population lived in rural areas, while in Varanasi district, 82.9% of the population lived in rural areas.
Hamirpur district is located in the Bundelkhand region of Uttar Pradesh. It is a largely rural district, with a population of over 1.8 million people. The district is known for its agriculture and its production of sugar cane.