In Accordance with Wilson and MacArthur's Theory of Island Biogeography

In accordance with Wilson and MacArthur's theory of island biogeography, the following equations represent the extinction and immigration rates of species of spiders on a small island. (I = immigration rate of species per year; E = extinction rate of species per year; S = number of species currently on the island.)
I = 3 ? 0.1S
E = 0.2S
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If there are five species on the island, the expected immigration rate is _______ species per year and the expected extinction rate is _______ species per year.

A) 1; 1
B) 1; 3.5
C) 2.5; 1
D) 5; 1.5