192. In the figure below, the temperature of the gas is 27 degrees Celsius and the mercury level is 75 cm. If we increase the temperature of the gas to 30 degrees Celsius, how many centimeters of mercury should we add to branch A so that the mercury level in branch M remains the same (i.e., stays at surface M)? [Figure: A U-tube manometer with a gas flask connected on the left side, mercury at the bottom, and branch A on the right side. Points M and M' are marked on the mercury surface.]
[(1)] 25
[(2)] 15
[(3)] 7.5
[(4)] 5.5
\textbf{192.} In the figure below, the temperature of the gas is 27 degrees Celsius and the mercury level is 75 cm. If we increase the temperature of the gas to 30 degrees Celsius, how many centimeters of mercury should we add to branch A so that the mercury level in branch M remains the same (i.e., stays at surface M)?
\textit{[Figure: A U-tube manometer with a gas flask connected on the left side, mercury at the bottom, and branch A on the right side. Points M and M' are marked on the mercury surface.]}
\begin{itemize}
\item[(1)] 25
\item[(2)] 15
\item[(3)] 7.5
\item[(4)] 5.5
\end{itemize}
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