Three infinitely long charge sheets are placed as shown in figure. ...

Three infinitely long charge sheets are placed as shown in figure. The electric field at point \( P \) is
\( -\sigma \)
\( z=-a \)
(a) \( \frac{2 \sigma}{\varepsilon_{0}} \hat{\mathbf{k}} \)
(b) \( -\frac{2 \sigma}{\varepsilon_{0}} \hat{\mathbf{k}} \)
(c) \( \frac{4 \sigma}{\varepsilon_{0}} \hat{\mathbf{k}} \)
(d) \( -\frac{4 \sigma}{\varepsilon_{0}} \hat{\mathbf{k}} \)