Answer:
Reflection
Explanation:
As you can see, its the same shape, and the same size...but it looked mirrored. ABC has been reflected over the y-axis to make DEF.
It's not rotation, because the shape has not been rotated, if so it would have been in a different position
It's not translation, because the shape didn't stay in the same format (facing one side).
So it must be reflection
Hope this helped!
Have a supercalifragilisticexpialidocious day!