If A→=2i^+j^+k^  and B→=i^+j^+k^  are two vectors then the unit vector

Unit vector perpendicular to A→  is A→×B→|A→×B→|=−j^+k^2Unit vector parallel to A→  is 2i^+j^+k^6  unit vector parallel to B→=i^+j^+k^3and therefore option (b) is not correct. Quite similarly options (c) and (d) are also wrong.