Explanation

(d) $\overrightarrow{A} \times \overrightarrow{B} = \left( \widehat{i} - 2\widehat{j} + 3\widehat{k} \right) \times (3\widehat{i} - 2\widehat{j} + \widehat{k})$
$= - 2\widehat{k} - \widehat{j} - 6\left( - \widehat{k} \right) - 2\widehat{i} + 9\widehat{j} - 6\left( - \widehat{i} \right) = 4\widehat{i} + 8\widehat{j} + 4\widehat{k}$
Modulus is $\sqrt{4^{2} + 8^{2} + 4^{2}} = \sqrt{32 + 64}$
$= \sqrt{96} = 4\sqrt{6}$ units.