AMC 12B 2004 Problem 7

A square has sides of length 10 , and a circle centered at one of its vertices has radius 10 . What is the area of the union of the regions enclosed by the square and the circle?

Answer Choices
A. 200+25 \pi
B. 100+75 \pi
C. 75+100 \pi
D. 100+100 \pi
E. 100+125 \pi