Answer:
It would be triangle A'B'C' with points (2, -1); (0, -3); and (2, -3).
Explanation:
If you were to translate triangle ABC down by two, then the y-value of each point would decrease by two. Hence, (2, 1) would become (2, -1); (0, -1) would become (0, -3); and (2, -1) would become (2, -3).