Tropical regions show greatest level of species richness because -

A.  Tropical latitudes have remained relatively undisturbed for millions of years, hence more time was available for species diversification.

B.  Tropical environments are more seasonal

C.  More solar energy is available in tropics

D.  Constant environments promote niche specialization.

E.  Tropical environments are constant and predictable.

Choose the correct answer form the options given below: