To translate the point (2, -5) to (2, -6), we are changing the y-coordinate from -5 to -6 while keeping the x-coordinate the same.
This means we need to apply a transformation to the y-coordinate only. The translation can be represented as:
\[ y' = y - 1 \]
In this case, if we let \(y\) be the original y-coordinate (-5), then the new y-coordinate \(y'\) after the translation becomes:
\[ y' = -5 - 1 = -6 \]
So, the appropriate function that represents this translation is:
\[ g(y) = y - 1 \]
Thus, the correct option is:
b. g(y) = y - 1