The easiest way to do this is to find a common denominator among all those denominators. Multiplying all those together gives you 2520. So now just get the equivalent numerator that goes along with it. -5/8 = -1575/2520; -7/9 = -1960/2520; -4/5 = -2016/2520; -3/7 = -1080/2520. Of course the least of these is the one that is most negative, which is the equivalent of -4/5. Next would be the equivalent of -7/9. Next is -5/8, and lastly, -3/7. So your choice is a.
