Answer
See the detailed answer below.
Work Step by Step
We know that the electric field of an infinite plane of charge is given by
$$E=\dfrac{\eta}{2\epsilon_0}$$
From the figure below, we can see that,
$\bullet$ At region 1:
$$E_{net,1}=E_B-E_C-E_A=\dfrac{\eta}{2\epsilon_0}-\dfrac{\eta}{4\epsilon_0}-\dfrac{\eta}{4\epsilon_0}$$
$$\boxed{\vec E_{net,1}=\bf 0\;\rm N/C}$$
$\bullet\bullet$ At region 2:
$$E_{net,2}=E_B+E_A-E_C=\dfrac{\eta}{2\epsilon_0}+\dfrac{\eta}{4\epsilon_0}-\dfrac{\eta}{4\epsilon_0}$$
$$\boxed{\vec E_{net,2}=\dfrac{\eta}{2\epsilon_0}\hat j}$$
$\bullet\bullet\bullet$ At region 3:
$$E_{net,3}=E_A-E_B-E_C=\dfrac{\eta}{4\epsilon_0}-\dfrac{\eta}{2\epsilon_0}-\dfrac{\eta}{4\epsilon_0}$$
$$\boxed{\vec E_{net,3}=-\dfrac{\eta}{2\epsilon_0}\hat j}$$
$\bullet\bullet\bullet\bullet$ At region 4:
$$E_{net,4}=E_C+E_A-E_B=\dfrac{\eta}{4\epsilon_0}+\dfrac{\eta}{4\epsilon_0}-\dfrac{\eta}{2\epsilon_0}$$
$$\boxed{\vec E_{net,4}=\bf 0\;\rm N/C}$$