Given the line L:x−13=y+12=z−3−1  and the planeπ:x−2y=z. of the following assertions, the only one that is always true is

[b] Since 3(1)+2(−2)+(−1)(−1)=3−4+1=0 ∴ Given line is ⊥ to the normal to the plane i.e., given line is parallel to the given plane. Also (1,−1,3) lies on the plane x−2y−z=0if 1−2(−1)−3=0 i.e. 1+2−3=0 Which is true ∴ L lies in planeπ.