The correct option is
A a1→i+a2→j+a3→k, where
a1=∓3/√14,a2=±2/√14,a3=±1/√14The vector perpendicular to both vector is vector parallel to the unit vector of resultant of cross product of the vectors given.
The cross product of both products =(^i+^j+^k)×(^i+2^j−^k)
=−3^i+2^j+^k
So, the unit vector parallel to the resultant vector is =±1√14(−3^i+2^j+^k)