\textbf{177-} How many electrons must be removed from a metal coin so that its electric charge becomes $+1\,\mu\text{C}$? $(e = 1.6 \times 10^{-19}\,\text{C})$
\begin{itemize}
\item[(1)] $1.6 \times 10^{6}$
\item[(2)] $1.6 \times 10^{12}$
\item[(3)] $6.25 \times 10^{6}$
\item[(4)] $6.25 \times 10^{12}$
\end{itemize}