b
(b) Let $A $ = $\left[ {\begin{array}{*{20}{c}}3&{ - 3}&4\\2&{ - 3}&4\\0&{ - 1}&1\end{array}} \right]$
Then, ${A_{11}} = 1,\,{A_{12}} = - 2,\,{A_{13}} = - 2$
${A_{21}} = - 1$ ,${A_{22}} = 3$,${A_{23}} = 3$
${A_{31}} = 0$, ${A_{32}} = - 4$,${A_{33}} = - 3$
$adj\,(A) = \left[ {\begin{array}{*{20}{c}}{{A_{11}}}&{{A_{21}}}&{{A_{31}}}\\{{A_{12}}}&{{A_{22}}}&{{A_{32}}}\\{{A_{13}}}&{{A_{23}}}&{{A_{33}}}\end{array}} \right]$ $ = \left[ {\begin{array}{*{20}{c}}1&{ - 1}&0\\{ - 2}&3&{ - 4}\\{ - 2}&3&{ - 3}\end{array}} \right]$.