Given triangle ABC with base AB fixed in length and position. As the vertex C moves on a straight line, the intersection point of the three medians moves on:
<spanclass=′latex−bold′>(A)</span>a circle<spanclass=′latex−bold′>(B)</span>a parabola<spanclass=′latex−bold′>(C)</span>an ellipse<spanclass=′latex−bold′>(D)</span>a straight line<spanclass=′latex−bold′>(E)</span>a curve here not listed