To translate a point on the coordinate plane from \((2, -5)\) to \((2, -6)\), we only need to change the \(y\)-coordinate.
The transition is from \(-5\) to \(-6\), which means the \(y\)-coordinate decreases by \(1\). Therefore, the translation can be represented by the function:
\[ g(y) = y - 1 \]
This function takes the current \(y\)-value and subtracts \(1\) from it, effectively moving downwards by \(1\) unit on the coordinate plane.
So, the correct function showing the appropriate translation is:
g(y) = y - 1.