When point T is reflected over a line of reflection, and the resulting point T′ has the same x-coordinate as point T, it indicates the vertical alignment of these points.
For the reflection of point T (with coordinates \((x, y)\)) to result in point T′ (with coordinates \((x, y′)\)) having the same x-coordinate, it means that the line of reflection must be a vertical line. This is because vertical reflection maintains the x-coordinates while potentially changing the y-coordinates.
Therefore, the correct answer is:
The line of reflection is vertical.
This is because a vertical line will not change the x-coordinate of point T when reflecting it, while potentially altering its y-coordinate.