Which of the following is true for an isometry?
a. the preimage and the image are congruent.
b. the preimage is larger than the image.
c. the preimage is smaller than the image.
d. the preimage is the same position as the image.

Isometry is defined as the  transformation that is invariant with respect to  the distance
The statement that is true for isometry that is corrrect is
The preimage and the image are congruent.
so correct option is A as both the preimage and image are congruent
hope it helps