The answer is A. organism, species, community.
Organizational hierarchy is the hierarchy of complex biological structures. From least complex to most complex the order is as following:
atom, molecule, organelle, cell, tissue, organ, organ system, organism, population, species, community, ecosystem, biome, biosphere.
So, A is the right choice:
Organism is the basic living system. The higher level is species - a group of organisms that are able to reproduce. The higher level is community - an interspecific group that includes interacting populations.
