The correct option is C rude
The word 'urbane' refers to being courteous and refined in manner.
Option A, rural refers to being rustic.
Option B, indifferent refers to having no particular interest or sympathy.
Option C, rude refers to being offensively impolite or bad mannered.
Option D, negative refers to being not desirable or optimistic.
Thus, according to the meaning, the word 'rude' is the opposite of the word 'urbane'.