A figure with vertical line symmetry is placed in the coordinate plane. Given that the points (1, 4) and (6, 4) are on the edges of the figure, which of the following points lies on the line of symmetry?

For vertical line symmetry, matching points lie the same horizontal distance from the line of symmetry. The x-coordinates 1 and 6 are equally far from their midpoint, (1 + 6) ÷ 2 = 3.5, so the symmetry line is x = 3.5. The point (3.5, 4) lies on that line, so the correct choice is C.

AI-written and checked against the verified answer.