Skew Line Definition (from Wikipedia): <em>"In three-dimensional geometry, skew lines are two lines that do not intersect and are not parallel." </em>-Wikipedia
<em>"Two lines that both lie in the same plane must either cross each other or be parallel, so skew lines can exist only in three or more dimensions."</em> -Wikipedia
Skew lines cannot lie in the same plane so A is correct and C is incorrect.
B and D are incorrect because our friend Wikipedia just said it was incorrect.
