设 3 阶方阵 $\boldsymbol{A}, \boldsymbol{B}$ 满足关系式 $\boldsymbol{A}^{-1} \boldsymbol{B} \boldsymbol{A}=6 \boldsymbol{A}+\boldsymbol{B} \boldsymbol{A}$, 其中 $\boldsymbol{A}=\left(\begin{array}{ccc}\frac{1}{3} & 0 & 0 \\ 0 & \frac{1}{4} & 0 \\ 0 & 0 & \frac{1}{7}\end{array}\right)$, 则 $\boldsymbol{B}=$
$\text{A.}$
$\text{B.}$
$\text{C.}$
$\text{D.}$