3456bt8Select two angles that, if congruent, would prove that line a is parallel to line b.

Answer: 1 and 5, 2 and 6, 3 and 7, 4 and 8.
Explanation:
The pairs of two angles given above follow the "corresponding angles theorem".
Hence, angles 1 and 5, 2 and 6, 3 and 7, 4 and 8 are congruent that prove that line a is parallel to line b.