b. (6) Let \(\mathbf{b}_A\) be the projection of \(\mathbf{b}\) onto the column space of \(A\). Find solution \(\mathbf{s}\) to \(A\mathbf{x} = \mathbf{b}_A\) such that \(\| \mathbf{s} \| \leq \| \mathbf{u} \|\) for all other solutions \(\mathbf{u}\).