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}