Since the slope of AB is change in y over change in x = (1 - -4) over (3 - 2), the slope is 5 over 1
If EF is perpendicular, then it’s slope MUST be the negative reciprocal or opposite sign & flip the fraction. EF slope is -1 over 5 ( or 1 over -5 which is the same)
So looking at the choices,
(2,-7) & (5, -1). -1 - -7 = 6 over 5 - 2 = 3 ...6/3= 2/1 NOPE
(0, 2) & (-1 , 7). 7 - 2 = 5 over -1 - 0 = -1 ... 5/-1. NOPE
(-3 , 2) & (7 , 0). 0 - 2 = -2 over 7 - -3 = 10. So -2 /10 which reduces to -1/ 5 WINNER!
Double check the last one: (7 , 4) & (6 , 1). 1 - 4 = -3 over 6 - 7 = -1 ... -3/-1 = 3/1 NOPE