An annulus is the region between two concentric circles. The concentric circles in the figure have radii b and c, with b>c. Let \overline{O X} be a radius of the larger circle, let \overline{X Z} be tangent to the smaller circle at Z, and let \overline{O Y} be the radius of the larger circle that contains Z. Let a=X Z, d=Y Z, and e=X Y. What is the area of the annulus?
Answer Choices
A. \pi a^{2}
B. \pi b^{2}
C. \pi c^{2}
D. \pi d^{2}
E. \pi e^{2}