Answer-
Lines e and c will be skew lines, if they lie in different planes and never intersect.
Solution-
Skew lines are lines that are in different planes, are not parallel, and do not intersect.
Parallel lines are lines that are in the same plane and do not intersect.
If they lie in the same plane but never intersect, then they are parallel lines.
So, option B is incorrect.
Option C and D are also incorrect.
Option A is the definition of skew lines. So it's the correct answer.