A circle of radius 2 is inscribed in a semicircle, as shown. The area inside the semicircle but outside the circle is shaded. What fraction of the semicircle’s area is shaded?

**Answer Choices**

A. \dfrac{1}{2}

B. \dfrac{\pi}{6}

C. \dfrac{2}{\pi}

D. \dfrac{2}{3}

E. \dfrac{3}{\pi}