The correct answer is The angles are congruent and the side lengths are proportional.
In a dilation, corresponding angles are congruent and corresponding side lengths are proportional. This means that the angles of the preimage and image are the same, and the side lengths of the preimage and image are related by a constant scale factor.
For example, if the scale factor of the dilation is 2, then each side length of the image is twice the corresponding side length of the preimage.
The other answer choices are incorrect. The angles are not proportional, and the side lengths are not congruent.
Therefore, the correct answer is The angles are congruent and the side lengths are proportional.