Two graphs labeled (c) and (d), showing a downward-opening parabola and a straight line with positive slope, respectively.
Graph (c) shows a parabolic curve opening downward with a vertex at (1.5, 1), crossing the x-axis at (0, 0) and (3, 0). Graph (d) shows a straight line with a positive slope passing through (-2, 0) and (0, 2).