The word "intent" is closest in meaning to which of following?

　　(A) purpose

　　(B) power

　　(C) effect

　　(D) invention

　　380. The smooth operation of an ant colony depends on ten to twenty different signals, most of which are pheromones(chemical signals triggering behavioral responses) .

　　The phrase "smooth operation" is closest in meaning to which of following?

　　(A) daily activity

　　(B) effective functioning

　　(C) delicate balance

　　(D) permanent location