Answer: I believe is is C, rotations and translations
Explanation:
This is because a congruent figure is one that has the same side lengths and angle measures.
Stretches and dilations are non-rigid transformations which change the length of the sides of a shape. While rotations, transformations, and reflections are rigid transformations which preserve angle measure and side length.
So, while a shape can be similar using stretches and dilations, they cannot be congruent.