The statement that is untrue about lines of symmetry is C. A line of symmetry is a vertical line through the middle of a figure.
While this is one example of a line of symmetry, the line doesn’t have to be vertical every time. As stated in answer choice B, lines of symmetry can come from any direction, as long as it evenly splits the figure. This can be vertical, horizontal, and/or diagonal.
I hope this helps. :)