设 $\boldsymbol{\alpha}_{1}, \boldsymbol{\alpha}_{2}, \boldsymbol{\alpha}_{3}$ 是 3 维向量空间 $\mathbf{R}^{3}$ 的一组基,则由基 $\boldsymbol{\alpha}_{1}, \frac{1}{2} \boldsymbol{\alpha}_{2}, \frac{1}{3} \boldsymbol{\alpha}_{3}$ 到基 $\boldsymbol{\alpha}_{1}+\boldsymbol{\alpha}_{2}, \boldsymbol{\alpha}_{2}+\boldsymbol{\alpha}_{3}, \boldsymbol{\alpha}_{3}+\boldsymbol{\alpha}_{1}$ 的过渡矩阵为 (）
A. $\left(\begin{array}{lll}1 & 0 & 1 \\ 2 & 2 & 0 \\ 0 & 3 & 3\end{array}\right)$.
B. $\left(\begin{array}{lll}1 & 2 & 0 \\ 0 & 2 & 3 \\ 1 & 0 & 3\end{array}\right)$.
C. $\left(\begin{array}{rrr}\frac{1}{2} & \frac{1}{4} & -\frac{1}{6} \\ -\frac{1}{2} & \frac{1}{4} & \frac{1}{6} \\ -\frac{1}{2} & -\frac{1}{4} & \frac{1}{6}\end{array}\right)$.
D. $\left(\begin{array}{rrr}\frac{1}{2} & -\frac{1}{2} & \frac{1}{2} \\ \frac{1}{4} & \frac{1}{4} & -\frac{1}{4} \\ -\frac{1}{6} & \frac{1}{6} & \frac{1}{6}-\end{array}\right)$.