The correct option is B Snob
'One who despises persons of lower social position' is Option B, Snob. Option A, Prim is a person who is very formal and proper in behavior and one who easily gets shocked by anything rude. Option C, Prig is a person who obeys the rules of correct behaviour and considers himself to be morally superior to others. Option D, Aristocrat is a class of people who hold high social rank. Thus, the options A, C and D are incorrect and the correct word for the given phrase is Option B, Snob.