In the diagram, YQZC is a rectangle with YC=8 and CZ=15. Equilateral triangles ABC and PQR, each with side length 9, are positioned as shown with R and B on sides YQ and CZ, respectively. The length of AP is
Answer Choices
A. 10
B. \sqrt{117}
C. 9
D. 8
E. \sqrt{72}