Two figures are congruent if they have the same shape and size. If the sizes are the same, then the angls and line segments are equal.
Reflections are isomeric transformation. They do not change the shape or size of a figure. It only mirrors the figure. Dilations can enlarge or reduce the size of a figure. A dilation with a factor below 1 reduces the figure. When the factor is 1, the size of the figure remains the same. When the factor is above 1, an enlargement occurs. Therefore, the correct option is D because the image is reduced and this changes its size.
D is the correct option