Quadrilateral H prime is the image of quadrilateral H after a sequence of transformations. If quadrilateral H prime is congruent to quadrilateral H, which transformations could have been used?
a dilation by a scale factor of 2 followed by a reflection
a rotation followed by a dilation by a scale factor of One-half
a reflection, a translation of 1 unit left, and then a dilation by a scale factor of 3
a translation of 6 units down, a rotation, and then a reflection