Ginkgo Trees (Ginkgo Biloba) Are "Living Fossils

Ginkgo trees (Ginkgo biloba) are "living fossils." Although ginkgos are native to China, they are now commonly planted in cities in the United States. Keeping in mind the principles of allopatric speciation, what might happen over time to the two populations of ginkgos?

A) Nothing, because ginkgo trees have evolved so slowly.
B) Environmental factors, such as air pollution, could result in the more rapid evolution of the trees in the cities of the United States.
C) Reproductive isolation could develop.
D) The two populations could develop into separate species.
E) All of the above