Which of the Following Best Explains Why a Given Biome

Which of the following best explains why a given biome is not found in each location where it could potentially exist?

A) Ecologists are presently unable to answer this question; biomes appear to develop randomly and are based on unknown factors.
B) Biomes consist of unique assemblages of organisms; each biome can occur at only one place on Earth.
C) Despite the appropriate climatic conditions, the bedrock at any given location may not produce the correct soils that would allow the biome to develop.
D) Where aquatic and terrestrial biomes meet, no type of biome is able to become established.