Why Are Plants Important to the Development of Karst

Why are plants important to the development of karst?

A) Primarily because openings adjacent to their roots serve as microchannels that allow water to enter the rock.
B) Primarily because the decay of large roots below the surface produces cavities which eventually enlarge to form caves.
C) Primarily because they supply organic acids that enhance the dissolution process.
D) Plants really do not play a role in the development of karst.