Ans: C
$\begin{array}{cl}
& h^2 -6h – 4k^2 -12k \\
= & h^2 -4k^2 – 6h – 12k \\
= & h^2 -(2k)^2 – 6h -12k \\
= & (h + 2k)(h – 2k) – 6(h + 2k) \\
= & (h + 2k)(h – 2k – 6)
\end{array}$
$\begin{array}{cl}
& h^2 -6h – 4k^2 -12k \\
= & h^2 -4k^2 – 6h – 12k \\
= & h^2 -(2k)^2 – 6h -12k \\
= & (h + 2k)(h – 2k) – 6(h + 2k) \\
= & (h + 2k)(h – 2k – 6)
\end{array}$
