The solution is B, (x, y, z) = (-1, 0, 0).
Eliminate z from the last two equations:
(y + 2z) + 2 (x - y - z) = 0 + 2 (-1)
2x - y = -2
Eliminate y from this and the first equation:
(-3x + 2y) + 2 (2x - y) = 3 + 2 (-2)
x = -1
Solve for y :
2x - y = -2
2 (-1) - y = -2
y = 0
Solve for z :
x - y - z = -1
-1 - 0 - z = -1
z = 0
