Three infinite long plane sheets carrying charge densities $\sigma _1 =+3 \sigma , \sigma _2 =+2 \sigma$ and $\sigma _3 =- \sigma$ are placed parallel to $x-z$ plane at $y=4a,y=3a$ and $y=a$ respectively. Electric field at point P is :

Question

$(A)\;zero \\ (B)\;\frac{-3 \sigma}{\in _0} \hat j \\ (C)\; \frac{-2 \sigma}{\in _0} \hat j \\ (D)\;\frac{3 \sigma }{\in _0} \hat j$