Answer
We can rank the situations according to the magnitude of the net electric field:
$(1) = (2) = (3)$
Work Step by Step
We can consider the net electric field at point $P_2$
By symmetry, the electric field at point $P_2$ due to the charge on Ring B is zero in all three cases.
The magnitude of the electric field at point $P_2$ due to the charge on Ring A is equal in all three cases.
Therefore, the magnitude of the net electric field at point $P_2$ is equal in all three cases.
We can rank the situations according to the magnitude of the net electric field:
$(1) = (2) = (3)$
