A unit square is rotated 45^{\circ} about its center. What is the area of the region swept out by the interior of the square?

**Answer Choices**

A. 1-\dfrac{\sqrt{2}}{2}+\dfrac{\pi}{4}

B. \dfrac{1}{2}+\dfrac{\pi}{4}

C. 2-\sqrt{2}+\dfrac{\pi}{4}

D. \dfrac{\sqrt{2}}{2}+\dfrac{\pi}{4}

E. 1+\dfrac{\sqrt{2}}{4}+\dfrac{\pi}{8}