Given: A(2,1), B(0,5), C(-1,2), AB and BC, lines x-2y=-5 and -x-3y=-10 through the midpoints of AB and BC and perpendicular to then. Use Gaussian elimination to find the intersection of the lines, the center of the circle containing points A, B, and C.
A. (-3,-1)
B. (-3,1)
C. (1,3)