Let WWW be the span of {(1,0,−1),(0,1,1)}\{(1, 0, -1), (0, 1, 1)\}{(1,0,−1),(0,1,1)}. Which vector is in W⊥W^\perpW⊥?
(1,1,1)(1, 1, 1)(1,1,1)
(0,1,0)(0, 1, 0)(0,1,0)
(1,0,1)(1, 0, 1)(1,0,1)
(1,−1,1)(1, -1, 1)(1,−1,1)