Which rule describes the composition of transformations that maps triangle ABC to triangle A'B'C'?
1) Rotate 90 degrees about the origin, followed by a reflection across the x-axis (x, y).
2) Reflect across the x-axis, followed by a 90-degree rotation about the origin (x, y).
3) Rotate 180 degrees about the origin, followed by a reflection across the x-axis (x, y).
4) Reflect across the y-axis, followed by a 180-degree rotation about the origin (x, y)..