Final answer:
A transformation that is not a rigid motion does not preserve distances and angles, which means the shape or size of the object may change after such transformation.
Step-by-step explanation:
When a transformation is not a rigid motion, it means that the transformation does not necessarily preserve distances and angles. The correct option describing a transformation that is not a rigid motion is b) It does not preserve distances and angles. This implies that when an object undergoes such a transformation, its shape or size may be altered, as in the cases of dilations, reflections on a non-linear axis, or more complex warping's of the space.