Which Statement Comparing Island Biogeography to Mainland Biogeography Is True

Which statement comparing island biogeography to mainland biogeography is true?

A) The slope of species richness to area should be steeper for mainland species than for island species.
B) Mainland sites should experience higher rates of immigration than island sites.
C) Mainland sites should experience higher rates of extinction than island sites.
D) On the mainland, extinction rate increases with area faster than immigration rate does, whereas the opposite is true for islands.