In the scenario described, Lexi folds the paper such that point C is on top of point D, which means that the fold is a line that bisects the segment CD. When she unfolds the paper, the intersection of the fold and segment CD is labeled point E, which is the midpoint of segment CD.
Since the fold gives a reflection through the line, and point E is the midpoint, the line that serves as the segment bisector of CD is CD itself.
Therefore, the correct response is:
CD¯¯¯¯¯¯¯¯