The lines are parallel.
Theorem: If two parallel lines are cut by a transversal, then same side interior angles are supplementary.
The angles measuring 16x + 4 and 80 are supplementary, so thjeir measures add to 180.
16x + 4 + 80 = 180
16x + 84 = 180
16x = 96
x = 6
Answer: A - 6