The correct option is
B Dissimilarity
Antonyms are words that have contrasting, or opposite, meanings.Choice B is correct. Uniformity means 'remaining the same in all cases' the opposite being 'dissimilarity', which means 'not the same at all'. For example: Although both the plants look alike the flowers are dissimilar in colour and form.
Choice A means ' unfriendliness' Choice C means 'in agreement of consistent' Choice D means 'protest against official policy'. Choice A, C and D are wrong.