Ans: B
$\begin{array}{cl}
& (27\cdot 9^{n+1})^3 \\
= & (3^3)^3 \cdot (3^2)^{3(n+1)} \\
= & 3^{9 +6n+6} \\
= & 3^{6n+15}
\end{array}$
$\begin{array}{cl}
& (27\cdot 9^{n+1})^3 \\
= & (3^3)^3 \cdot (3^2)^{3(n+1)} \\
= & 3^{9 +6n+6} \\
= & 3^{6n+15}
\end{array}$
