A dart board is a regular octagon divided into regions as shown. Suppose that a dart thrown at the board is equally likely to land anywhere on the board. What is the probability that the dart lands within the center square?
Answer Choices
A. \dfrac{\sqrt{2}-1}{2}
B. \dfrac{1}{4}
C. \dfrac{2-\sqrt{2}}{2}
D. \dfrac{\sqrt{2}}{4}
E. 2-\sqrt{2}