Triangle ABC, with vertices A(3, 0), B(2, 4), and C(4, 2), undergoes a transformation to form triangle A'B'C' with vertices A'(3,0), B'(2, -4), and C'(4, -2). The type of transformation ABC undergoes is a _________.
A 360° clockwise rotation
B reflection across the x-axis
C reflection across the y-axis
D translation 1 unit right and 1 unit up
E dilation by a scale factor of 0.5
