The vector equation is:
\[
\begin{bmatrix} 2 \\ 0 \end{bmatrix} x_1 + \begin{bmatrix} 1 \\ 7 \end{bmatrix} x_2 + \begin{bmatrix} -3 \\ 0 \end{bmatrix} x_3 = \begin{bmatrix} 2 \\ -33 \end{bmatrix}
\]
The matrix equation is:
\[
\begin{bmatrix} 2 & 1 & -3 \\ 0 & 7 & 0 \end{bmatrix} \begin{bmatrix} x_1 \\ x_2 \\ x_3 \end{bmatrix} = \begin{bmatrix} 2 \\ -33 \end{bmatrix}
\]
Thus, the correct choice for the vector equation is:
B. \(\boxed{\begin{bmatrix} 2 & 1 & -3 \\ 0 & 7 & 0 \end{bmatrix} \begin{bmatrix} x_1 \\ x_2 \\ x_3 \end{bmatrix} = \begin{bmatrix} 2 \\ -33 \end{bmatrix}}\)