A square of side length 1 and a circle of radius \sqrt{3} / 3 share the same center. What is the area inside the circle, but outside the square?
Answer Choices
A. \dfrac{\pi}{3}-1
B. \dfrac{2 \pi}{9}-\dfrac{\sqrt{3}}{3}
C. \dfrac{\pi}{18}
D. \dfrac{1}{4}
E. 2 \pi / 9