据个例子: x = 450,y=350-->x+y = 800; y = 450-->x+y = 900 (but x should be>=450, and y should be < 450, in that case it results in different outcome) similiar to (2) if x= 450; y =399 => x+y <850 --> 800; x = 499, y =399=> x+y = 898-->900; yields diff outcome as well. So it should be E. |