Linear algebra

Question

. The solution of the system of equations  x+y+z =4, x-y+z =0, x+y+z =5 is

1.     x=2, y=2, z=0
2.     x=1, y=4, z=1
3.     x=2, y=4, z=3
4.     x=1, y=2, z=1