Hướng dẫn

Ta có: ${{z}^{4}}-{{z}^{2}}-12=0\Leftrightarrow \left[ \begin{align}

  & {{z}^{2}}=4 \\

 & {{z}^{2}}=-3=3{{i}^{2}} \\

\end{align} \right.\Leftrightarrow \left[ \begin{align}

  & {{z}_{1}}=2 \\

 & {{z}_{2}}=-2 \\

 & {{z}_{3}}=i\sqrt{3} \\

 & {{z}_{4}}=-i\sqrt{3} \\

\end{align} \right.$.

Khi đó: $\text{T}=\left| {{z}_{1}} \right|+\left| {{z}_{2}} \right|+\left| {{z}_{3}} \right|+\left| {{z}_{4}} \right|=\left| 2 \right|+\left| -2 \right|+\sqrt{{{0}^{2}}+{{\left( \sqrt{3} \right)}^{2}}}+\sqrt{{{0}^{2}}+{{\left( -\sqrt{3} \right)}^{2}}}=4+2\sqrt{3}\Rightarrow $ Chọn đáp án C.