\(\rm \vec A, \vec B\) and \(\rm \vec C\) are unit vectors. \(\rm \vec A \) is perpendicular to both \(\rm \vec B\) and \(\rm \vec C\) and angle between \(\rm \vec B\) and \(\rm \vec C\) is 30° Then vector \(\rm \vec A, \) is -
1
± (\(\rm \vec B\) × \(\rm \vec C\))
2
± \(\frac{1}{2}\)(\(\rm \vec B\) × \(\rm \vec C\))
3
± 2(\(\rm \vec B\) × \(\rm \vec C\))
4
± \(\frac{1}{3}\)(\(\rm \vec B\) × \(\rm \vec C\))