If the coordinates of the vertices of a parallelogram are (-2,3), (3,1), (-1,4) and (-6,6), then one of its diagonals has a slope of

A. -1
B. -2/5
C. 5/9
D. 1

Can you find the slope of a line joining two points? Assuming the vertices are listed in order around the figure, then the diagonals are lines between

(-2,3) and (-1,4)
and
(3,1) and (-6,6)

One of those lines should have a slope listed in the choices.

If you can't figure the slope, review that material in your text, or just google it.