The correct option is C common
Let’s examine the sentence: “Caricature, a type of exaggeration is common used in political cartoons.” The word ‘common’ is used between two verbs and so it should be an adverb. An adverb is a word or phrase that modifies the meaning of an adjective, verb, or other adverb. However, ‘common’ is a noun and not an adverb; the adverb corresponding to ‘common’ is ‘commonly.’ So, ‘common’ in this sentence should be replaced by ‘commonly.’ Hence, the word or phrase that must be changed for the sentence to be correct is indicated by Option C. Option C is the correct answer.