Help with geometry please

Can someone please answer number 5 on this test. I'm a little confused on how to do it. If you can explain how you did it, that would be great.

Number 5 on page 2 of this test
http://www.jmap.org/JMAP/RegentsExamsand…

Thanks!

a pair of lines /segments are co=planar when they lie on the same rectangle
if you connect four vertices
AB and DH don not lie on the same rectangle
neither DC and AE
nor CG and EF

BC and EH on the other hand lie on the rectangle
BCHE
where BC//EH
and BE//HC