Rectangle ABCD is shown below. If rectangle ABCD is transformed to create rectangle A'B'C'D', and the coordinates of rectangle A'B'C'D' are A'(x, -y), B'(x, -y), C'(x, -y), and D'(x, -y), which transformation has occurred? *
Translation
Reflection across the y-axis
Rotation of 90 degrees around the origin
Reflection across the x-axis