Segment AB is being dilated with the center at the origin. The image of A, point A prime, has coordinates of (3.2, 6.4). What is the scale factor of the dilation and the coordinates of point B prime?

On a coordinate plane, point A prime is (3.2, 6.4), point B prime is (negative 4, negative 6) and point A is (4, 8).
The scale factor is 0.8 and the coordinates of point B prime are (–3.2, –4.8).
The scale factor is 1.25 and the coordinates of point B prime are (–3.2, –4.8).
The scale factor is 0.8 and the coordinates of point B prime are (–5, –7.5).
The scale factor is 1.25 and the coordinates of point B prime are (–5, –7.5).