Similar polygons are made through scaling either by stretching or squeezing the sides all by a common ratio. Here, the size changes. Congruent polygons are made by shifting or reflecting their position. Here, the size does not change.
Choice A has a dilution (or squeezing) and a translation (shifting). That makes similar polygons.
Choice B has a rotation. Nope.
Choice C has a shifting and a reflection. Nope.
Choice D has a rotation and shifting. Nope.
Thus choice A is best.
