YAY!!! ANOTHER PERSON FRON ED-GENUITY!!!
All of the letters are equal to 90 degrees so the answer would be C.
Hope I helped!
Notice that the reflection is over a line of the form x=constant; in this case, the y-coordinate of the reflected point stays the same while the x-coordinate changes as expressed by the transformation below

Hence, in our case

Transform points N, M, and O accordingly,

<h2>Therefore, the answer is the first option (top to bottom)</h2>
By the general application of cumulative property of addition :
x + y = y + x
For sure