The Existence of Platanus × Hybrida Is Indicative of the Fact

The existence of Platanus × hybrida is indicative of the fact that:

A) fertile hybrids between species can occur.
B) members of different species do not ordinarily interbreed in nature.
C) members of different species should really be considered part of the same species.
D) morphologically distinct species should be considered subspecies.
E) the London plane tree should be considered a separate species in its own right.