Final answer:
The scale factor of the dilation is 1.
Step-by-step explanation:
To find the scale factor, we need to compare the range of the range to the original pre-image. If the range of the range is congruent to the pre-image, it means that all the distances in the range are the same as the corresponding distances in the pre-image. In other words, the scale factor is 1. Therefore, option a. 1 is the correct answer.