The correct option is
B urban
Option B: 'Urban' is the opposite of 'rural'. The given sentence mentions different regional groups, one belonging to the city (urban) and one belonging to the villages (rural).
From the options, 'urban' is the only option that fits into the same category as 'rural', which represent different classes of people in a city and village, respectively.
Hence option B is correct.
Options A, C and D: 'Modern' refers to the present times, 'fashionable' describes the dressing sense of a person and 'educated' refers to a class of people who have studied.
These words do not fall in the same category as 'rural'. As a result, the meanings formed are ambiguous.
Hence options A, C and D are incorrect.