The definition of alternate interior angles is that If two parallel lines are cut by an external line, then the alternate interior angles are alternate angles.
So, the angles are alternate interior angles.
Therefore, options B and C can be correct. But as, we see both the angles are not equal. Hence, both are not congruent.
Also, two angles are called supplementary if they sum up to 180. From the figure, both the angles are summing up to 180.
Therefore, C) supplementary, consecutive interior angles is the right option.