151 -- If the number $2^n - 1$ is divisible by 217, how many two-digit values does $n$ have?
[(1)] $4$
[(2)] $5$
[(3)] $6$
[(4)] $7$
\textbf{151 --} If the number $2^n - 1$ is divisible by 217, how many two-digit values does $n$ have?
\begin{itemize}
\item[(1)] $4$
\item[(2)] $5$
\item[(3)] $6$
\item[(4)] $7$
\end{itemize}