设 $\pmb{\alpha}_{1} = \begin{pmatrix} 0 \\ 0 \\ c_{1} \end{pmatrix}, \pmb{\alpha}_{2} = \begin{pmatrix} 0 \\ 1 \\ c_{2} \end{pmatrix}, \pmb{\alpha}_{3} = \begin{pmatrix} 1 \\ -1 \\ c_{3} \end{pmatrix}, \pmb{\alpha}_{4} = \begin{pmatrix} -1 \\ 1 \\ c_{4} \end{pmatrix}$ , 其中 $c_{1}, c_{2}, c_{3}, c_{4}$ 为任意常数, 则下列向量组线性相关的为( ) (A) $\alpha_{1}, \alpha_{2}, \alpha_{3}$ . (B) $\pmb{\alpha}_{1}, \pmb{\alpha}_{2}, \pmb{\alpha}_{4}$ . (C) $\alpha_{1}, \alpha_{3}, \alpha_{4}$ . (D) $\alpha_{2}, \alpha_{3}, \alpha_{4}$ .