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