Answer
We can rank the five regions according to the magnitude of the x component of the electric field within them:
$2 \gt 4 \gt 1 = 3 = 5$
Work Step by Step
We can write the general equation for an electric field:
$E = -\frac{\Delta V}{\Delta x}$
We can see that the absolute value of the slope of the electric potential versus position graph is the magnitude of the electric field.
Region 2 has the steepest slope.
Region 4 has the next steepest slope.
Region 1, Region 3, and Region 5 all have a slope of zero.
We can rank the five regions according to the magnitude of the x component of the electric field within them:
$2 \gt 4 \gt 1 = 3 = 5$
