Which of the Following Was a Finding of Tansley's Experiments

Which of the following was a finding of Tansley's experiments with bedstraw plants?

A) The species that was restricted to acidic soils excluded the species that was adapted to calcareous soils when grown on acidic soils.
B) The species that grew on calcareous soils was physiologically incapable of growing on acidic soils.
C) The species that grew on acidic soils was physiologically incapable of growing on calcareous soils.
D) The two species did not compete with each other when grown together.