We have to choose the correct answer for the center of the circumscribed circle of a triangle. The center of the circumscribed circle of a triangle is where the perpendicular bisectors of a triangle intersects. In this case P1P2 and Q1Q2 are perpendicular bisectors of sides AB and BC, respectively and they intersect at point P. S is the point where the angle bisectors intersect ( it is the center of the inscribed circle ). Answer: P.
