Answer:
C. A reflection over the line y = -x
Explanation:
You need to reflect that over a line that goes between the two of them. That imaginary line has a rise of -1 (it goes down 1 unit) and a run of 1 (it goes one unit to the right). In other words, the slope is -1. The line should also have a y-intercept of 0 it starts at (0,0).
Put that information in slope-intercept form
y = -1x + 0
You can take out the 0 because it adds nothing to the equation, and you can remove the one because of the same reason, but leave the negative sign.
y = -x