Define a parabola as a set of points. What is the relationship of the points to the lines and points associated with the​ parabola? Choose the correct answer below. A. The parabola is the set of points such that the sum of the distances from the focus and the directrix is a constant. B. The parabola is the set of points equidistant from the focus and the vertex. C. The parabola is the set of points equidistant from the focus and the directrix. D. The parabola is the set of points such that the sum of the distances from the focus and the vertex is a constant. E. The parabola is the set of points equidistant from the vertex and the directrix.