C)90 because if it go all the way around it would be 180 and I don't see that
Judging by the question you have provided I came to the conclusion that you have already solved your own problem!
If the goal is to find X when X=-15 then your answer for X should be -15!
If this is not the entire equation please post the entire one!
Hope this helped!
-Blake
<span>D. 7/8
Hope it helped :)</span>