According to the probles represented above, there is addition of two angles which makes it totally clear. I am pretty sure that the answer with the actual reason of this task is the second option <span>B. Angle Addition Postulate, as you can see a couple of new angles in there :)
Regards!</span>
Hello
The asnwer is C.
Have a nice day
Well, first off, let's find what is the slope of BC

now, a line perpendicular to that one, will have a negative reciprocal slope, thus

now, we know the slope "m" of AB is -2 then, thus