To reflect a figure across an axis means to mirror it. This means that that triangle in the picture must be mirrored across the x - axis. Since your problem is only asking for the coordinate of H, this will take much less time.
Since this is getting reflected across the x - axis, the x value of the coordinate is going to stay the same. So we know then that the x value is going to be -4. Now all you have to do is find the y value, but switch the sign. The y value of H is 5, so the reflected value will be -5.
With this info we can figure that the coordinate will be (-4,-5), meaning the answer is C!
Hope this helps! :)
