The equation of the plane containing the line $\frac{x-x_1}{l} = \frac{y-y_1}{m} = \frac{z- z_1}{n}$ is $a(x-x_1) + b(y-y_1) + c ( z - z_1) = 0$, where :

Question

( A ) $\frac{a}{l} = \frac{b}{m} = \frac{c}{n}$
( B ) $ax_1 + by_1 + cz_1 = 0$
( C ) $al + bm + cn = 0$
( D ) $l m_1 + my_1 + nz_1 = 0$