Triangle PQR is similar to triangle XYZ. Which statement is true?

A. The slope of QR is equal to the slope of XZ.
B. The slope of PR is equal to the slope of XZ.
C. The slope of PR is equal to the slope of YZ.
D. The slope of QR is equal to the slope of XY.

None of the statements are necessarily true. Similar triangles have proportional side lengths but do not necessarily have the same slope for corresponding sides or any relationship between the slopes of their sides. The correct answer is E. None of the above.