Which Statement Is Closest to Alfred Russel Wallace's Early Hypothesis

Which statement is closest to Alfred Russel Wallace's early hypothesis for the higher diversity of life in the tropics?

A) The tropics have a larger land area than other parts of the globe, and thus can support species with larger population sizes. Such species are less prone to extinction.
B) The tropics have a larger land area than other parts of the globe, and thus can support species with larger population sizes. Such species are more apt to produce new species.
C) The tropics are more climatically stable than other parts of the globe, and thus can support species with larger population sizes. Such species are less prone to extinction.
D) The tropics are more climatically stable than other parts of the globe, so tropical species have had more time to diversify than those in areas with severe climatic conditions.