x = 4 and y = 0 are solution of

For option one:  

x + y = 4

x = 4 & y = 0 gives L.H.S = 4 + 0 = 4 = R.H.S

2x - y = 8

x = 4 & y = 0 gives L.H.S = 2(4) - 0 = 8 = R.H.S

For option two: 

2x + 2y = 8

x = 4 & y = 0 gives L.H.S = 2(4) + 2(0) = 8 = R.H.S

4x - 2y = 16

x = 4 & y = 0 gives L.H.S = 4(4) - 2(0) = 16 = R.H.S

Therefore, both A & B are correct.