Ans: A
$\begin{array}{cl}
& 3^{2n} \cdot 4^n \\
= & 3^{2n} \cdot (2^2)^n \\
= & 3^{2n} \cdot 2^{2n} \\
= & (3\cdot 2) ^{2n} \\
= & 6^{2n}
\end{array}$
$\begin{array}{cl}
& 3^{2n} \cdot 4^n \\
= & 3^{2n} \cdot (2^2)^n \\
= & 3^{2n} \cdot 2^{2n} \\
= & (3\cdot 2) ^{2n} \\
= & 6^{2n}
\end{array}$
