The correct response is:
Amias can dilate circle A by a factor of b/a and show that the circles now coincide. Because a sequence of transformations maps circle A onto circle B, circle A is similar to circle B.
This is because dilation is a geometric transformation that preserves the shape of the figure. Since similarity is defined by whether one shape can be transformed into another via scaling (dilation), translation, and rotation, Amias's dilation of circle A to match circle B demonstrates their similarity.