To change the equation from \( y = 23x - 4 \) to \( y = 23x \), you need to eliminate the constant term (-4).
This can be achieved by shifting the graph up by 4 units. Shifting the graph up 4 units will add 4 to the y-values, resulting in the new equation \( y = 23x \).
So the correct transformation is:
Shift the graph up 4.