From cells to tissues to organs to organ systems to the organism itself. That is the hierarchy of cytology to most eukaryotic organisms. Cell is the basic unit of every living organism. This basic unit has specialization that functions differently for each pattern of structural and functional processes.
Answer is A. (commensalism)
assuming there is no benefit to the pitcher plant from the mosquito larvae,
commensalism means one species benefits while the other derives neither benefit nor harm
