the correct answer to this statement is A. producers use it. this is the correct answer because to creat photosynthesis you need a producer because decomposers get rid of things , so D is incorrect. scavenggers dont use it because they are not in the cycle of photosynthesis , so C is wrong. consumers basically eat thing and they have a small art in photosynthesis, so B is incorrect. which leaves you with A producers and producers make things which happens alot in photosynthesis, so A Producers use it is the correct responce.