设 $\alpha_1=\left(\begin{array}{l}a_1 \\ a_2 \\ a_3\end{array}\right), \alpha_2=\left(\begin{array}{l}b_1 \\ b_2 \\ b_3\end{array}\right), \alpha_3=\left(\begin{array}{l}c_1 \\ c_2 \\ c_3\end{array}\right)$ ，则三条直线 $a_1 x+b_1 y+c_1=0, a_2 x+b_2 y+c_2=0, a_3 x+b_3 y+c_3=0$ (其中 $a_i^2+b_i^2 \neq 0, i=1,2,3$ ) 交于一点的充要条件是
A. $\alpha_1, \alpha_2, \alpha_3$ 线性相关
B. $\alpha_1, \alpha_2, \alpha_3$ 线性无关
C. $r\left(\alpha_1, \alpha_2, \alpha_3\right)=r\left(\alpha_1, \alpha_2\right)$
D. $\alpha_1, \alpha_2, \alpha_3$ 线性相关， $\alpha_1, \alpha_2$ 线性无关