Which organisms recycle the organic molecules of dead organisms at all trphic levels and then put the nutrients from those organic molecules back into the environment?

Decomposers are the organisms that recycle the organic molecules of dead organisms at all trophic levels and then put the nutrients from those molecules back into the environment. Decomposers are organisms that decomposes, or breaks down, organic material such as the remains of dead organisms. These includes bacteria and fungi. A dead organism provides nutrients for decomposers like bacteria and fungi to use in order to grow and reproduce, propagating their own species. 

Well i had the same answer, so the correct answer would be a. but in this case it would be the one with plasma membrane and cell wall circled that is next to the hairy pill type of thing.