Which ordered triple represents all of the solutions to the system of equations shown below?
2x ­- 2y ­- z = 6
-x + y + 3z = -­3
3x ­- 3y + 2z = 9

a) (­-x, x + 2, 0)
b) (x, x ­- 3, 0)
c) (x + 2, x, 0)
d) (0, y, y + 4)