Lời giải

Chọn C

Ta có: $M\left( 2;0 \right)$là trung điểm BC$\left\{ \begin{align}& 2=\frac{{{x}_{B}}+(-2)}{2} \\ & 0=\frac{{{y}_{B}}+(-4)}{2} \\ \end{align} \right.$$\Leftrightarrow \left\{ \begin{align}& {{x}_{B}}=6 \\ & {{y}_{B}}=4 \\ \end{align} \right.$$\Rightarrow B\left( 6;4 \right)$

$G\left( 0;4 \right)$là trọng tâm tam giác ABC $\left\{ \begin{align}& 0=\frac{{{x}_{A}}+6+(-2)}{3} \\ & 4=\frac{{{y}_{A}}+4+(-4)}{3} \\ \end{align} \right.$$\Leftrightarrow \left\{ \begin{align}& {{x}_{A}}=-4 \\ & {{y}_{A}}=12 \\ \end{align} \right.$$\Rightarrow A\left( -4;12 \right)$