Answer:
C. Circumcenter
Explanation:
Definitions:
Orthocenter is the point where the three "altitudes" of a triangle meet. An "altitude" is a line that goes through a vertex and is at right angles to the opposite side.
Incenter is the center of an inscribed circle (the circle that fits perfectly inside triangle, just touching all sides). It is where the "angle bisectors" (lines that split each angle in half) meet.
Circumcenter is the center of circumscribed circle. It is where the "perpendicular bisectors" (lines that are at right angles to the midpoint of each side) meet.
Centroid (or center of mass) of a triangle is the point where the three medians of the triangle meet.
As you can see from the definitions, point P is circumcenter, because it is the point of perpendicular bisectors intersection.