If `l_(1), m_(1), n_(1)` and `l_(2), m_(2), n_(2)` are the direction cosines of two lines and `l`, m, n are the direction cosines of a line perpendicular to the given two lines, then

Options

A. `(l)/(|(m_(1),n_(1)),(m_(2),m_(2))|)=(-m)/(|(l_(1),n_(1)),(l_(2),n_(2))|)=(n)/(|(l_(1),n_(1)),(l_(2),n_(2))|)`
B. `(l)/(|(m_(1),n_(1)),(m_(2),m_(2))|)=(-m)/(|(l_(1),n_(1)),(l_(2),n_(2))|)=(-n)/(|(l_(1),n_(1)),(l_(2),n_(2))|)`
C. `(-l)/(|(m_(1),n_(1)),(m_(2),m_(2))|)=(-m)/(|(l_(1),n_(1)),(l_(2),n_(2))|)=(n)/(|(l_(1),n_(1)),(l_(2),n_(2))|)`
D. `(l)/(|(m_(1),n_(1)),(m_(2),m_(2))|)=(m)/(|(l_(1),n_(1)),(l_(2),n_(2))|)=(n)/(|(l_(1),n_(1)),(l_(2),n_(2))|)`

Answer

A