Answer: Choice D) sides MN and PO
==========================================================
Explanation:
Refer to the diagram below. We have parallelogram MNOP such that we start at M, and work counterclockwise around the figure. You could work clockwise and it would be the same idea.
We see that side MN is opposite side PO. These are the two horizontal sides. The arrow markers tell us which pairs of sides are parallel. So this is why choice D is the answer.
--------------
Extra info:
- Choice A is not the answer because segments MN and ON share a common point N. Note how "N" shows up in both "MN" and "ON". This makes them adjacent sides rather than opposite sides. You can think of "adjacent" as to mean "next door neighbor".
- Choice B is ruled out because segment MO is not an exterior side. Instead, it is a diagonal.
- Choice C is ruled out for similar reasoning as choice A. This time segments PM and PO have the shared common vertex of point P.
