Find a linearly independent set $S$ so that the span of $S$, $\spn{S}$, is row space of the matrix $B$, and $S$ is linearly independent. \begin{equation*} B= \begin{bmatrix} 2 & 3 & 1 & 1\\ 1 & 1 & 0 & 1\\ -1 & 2 & 3 & -4 \end{bmatrix} \end{equation*}