A long thin rod lies along the x-axis with one end at origin . it has a uniformly charge density lamdac/m. assuming it to infinite in the length the electric field point x=-a on the x-axis will

$$\begin{gathered} \left(1\right) \frac{\lambda }{\pi {\in }_{0}a} \\ \left(2\right) \frac{\lambda }{2\pi {\in }_{0}a} \\ \left(3\right) \frac{\lambda }{4\pi {\in }_{0}a} \\ \left(4\right) \frac{2\lambda }{\pi {\in }_{0}a} \end{gathered}$$