A) quickerB) most quicklyC) quickestD) more quicklyThe correct answer is: D) more quickly Explanation: When comparing two or more actions, we use the comparative form of the adverb. The adverb form of “quick” is quickly. Its comparative is more quickly (not quicker, since “quicker” is an adjective, not an adverb). Sentence: He ran more quickly than anyone else in the race.