“If the alternate exterior angles are congruent, then the lines are parallel.”

What is the inverse of the statement?

If the lines are parallel, then the alternate exterior angles are congruent.

If the alternate exterior angles are congruent, then the lines should be parallel.

If the alternate exterior angles are not congruent, then the lines are not parallel.

If the lines are not parallel, then the alternate exterior angles are not congruent.