Hello there!
Let's just use points H and H' to help us answer this problem.
Point H has coordinates of (-2, 2)
Point H' has coordinates of (-2, -2)
After comparing these two points, you may notice that the x-coordinate didn't change, but the y-coordinate switched signs during the transformation.
Thus, you can safely pick the third choice.
The third choice is the general definition for a reflection across the x-axis, so note that this may be useful in the future! Hope this helps! :)