Final answer:
Translation is the only transformation that is an isometry.
Step-by-step explanation:
An isometry is a transformation that preserves distances between points. Out of the given options, translation is the only transformation that is an isometry. A translation simply moves every point in a figure in the same direction and distance, without changing its size or shape.
On the other hand, dilation changes the size of a figure by stretching or compressing it. Rotation changes the orientation of a figure by rotating it around a fixed point. And reflection changes the orientation of a figure by flipping it across a line of symmetry.
Therefore, the correct answer is A) Translation.