IMO E
y-x = +ve ==> y > X
1. y> o ==> Nothing about x. Insufficient
2. x = 1-y
x+y = 1
Not sufficient
combining both, x+y = 1 and y >0
==> x can be +ve or -ve. It is not mentioned that x and y are integers.
if, x = -2, y = 3, x+y =1 and y>0 ==> y-x = +ve
if x = 0.6, y = 0.4, x+y =1 and y>0 ==> y-x = -ve