Answer:
 I. APY = (1 +r/n)^n -1
 II. 4.0474%
 III. 4.0487%
 IV. 4.0398%
 V. Account B
Step-by-step explanation:
I. The expression is ...
 APY = (1 +r/n)^n -1
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II–IV. See the attached. (When calculations are tedious and repetitive, a spreadsheet is helpful.)
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V. The account compounded quarterly has the highest APY, account B.