Given the polygons graphed, you need to remember that, by definition, a Similarity Transformation is a combination or a composition of rigid transformations (Translation, Reflection, Rotation) or Dilations.
In this case, you can identify that Polygon 4 can be obtained after these transformations:
1. Dilation of Polygon 1 using this scale factor:
2. A Rotation (a rigid transformation).
Hence, the answer is: Option C.