Four concentric circles share the same center. The smallest circle has a radius of 1 inch. For n greater than 1, the area of the nth smallest circle in square inches,A_{n} , is given by A_{n}=A_{n-1}+(2n-1) \pi What is the sum of the areas of the four circles, divided by the sum of their circumferences, in inches?
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A1
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B1\frac{1}{2}
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C2
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D2\frac{1}{2}
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E3
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正确答案: B