A7. The product of the numbers $3 \cdot 16 \cdot 45 \cdot 81$ is divisible by $6^{n}$. Determine the largest possible $n$.
(A) $n=3$
(B) $n=4$
(C) $n=5$
(D) $n=6$
(E) $n=7$
A7. The product $3 \cdot 16 \cdot 45 \cdot 81$ can also be written as $3 \cdot 16 \cdot 45 \cdot 81=6^{4} \cdot 3^{3} \cdot 5$. From this, it follows that $n=4$.