Given a triangle with vertices A, B, and C. the center of the circle that circumscribes the triangle is: (a) the intersection of any two perpendicular bisectors of the triangle.
(b) the intersection of any two altitudes of the triangle.
(c) the intersection of any two angle bisectors of the triangle.
(d) the intersection of any two median of the triangle.
(e) the intersection of an angle bisector and an altitude of the triangle.

Thanks in advance!