An infinitely long line, with uniform positive charge density, lies along the $\text{z}$-axis. In cylindrical coordinate $\left ( r,\varnothing ,z \right )$, at any point $\vec{P}$ not on the $\text{z}$-axis, the direction of the electric field is
- $\hat{r}$
- $\hat{\varnothing }$
- $\hat{z }$
- $\frac{\left ( \hat{r}+\hat{z} \right )}{\sqrt{2}}$