\textbf{152 --} The four-digit number $\overline{aabb}$, whose square root is the two-digit number $\overline{cc}$, and $\overline{cc} = a - b$. What is $a - b$?
\begin{itemize}
\item[(1)] $2$
\item[(2)] $3$
\item[(3)] $4$
\item[(4)] $5$
\end{itemize}