These two angles are a linear pair. They are supplementary (ie they add to 180) and they are adjacent. We know they are supplementary because line WXZ is a straight line. Put another way: point X is on line WZ.
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Side notes:
Choice A is only true if we have a 90 degree angle at point X
Choice B is never true because of the remote interior angle theorem
Choice D is only true if we have an isosceles triangle with XZ = YZ.
