Ans: A
$\begin{array}{cl}
& 8^{222} \cdot 5^{666} \\
= & (2^3)^{222} \cdot 5^{666} \\
= & 2^{3 \times 222} \cdot 5^{666} \\
= & (2 \cdot 5) ^{666} \\
= & 10^{666}
\end{array}$
$\begin{array}{cl}
& 8^{222} \cdot 5^{666} \\
= & (2^3)^{222} \cdot 5^{666} \\
= & 2^{3 \times 222} \cdot 5^{666} \\
= & (2 \cdot 5) ^{666} \\
= & 10^{666}
\end{array}$
