In the figure electric field at $P_1$ is $\bar{E_1}$ and electric field at $P_2$ is $\bar{E_2}$ Find the angle between $\bar{E_1}$ and $\bar{E_2}$

Question

$\begin{array}{1 1} (a) \;0^{\circ} \\ (b) \;45^{\circ}\\ (c) \;180^{\circ} \\ (d) \;90^{\circ}\end{array} $