Simplify: $2a^2 (3a^2-4)+4a(2a^2+3 )-12 (a-1)$

Question

$\begin{array}{1 1} 6a^2+8a^3+8a^2+12 \\ 6a^2+8a^3+8a^2+12 \\ 6a^2+8a^3-8a^2+12 \\ 6a^5+12 \end{array} $