A charged particle (electron or proton) is introduced at the origin ( $x=0, y=0, z=0$ ) with a given initial velocity $\overrightarrow{\mathrm{v}}$. A uniform electric field $\overrightarrow{\mathrm{E}}$ and a uniform magnetic field $\overrightarrow{\mathrm{B}}$ exist everywhere. The velocity $\vec{v}$, electric field $\vec{E}$ and magnetic field $\vec{B}$ are given in columns 1,2 and 3 respectively. The quantities $\mathrm{E}_0, \mathrm{~B}_0$ are positive in magnitude.

In which case will the particle describe a helical path with axis along the positive z-direction ?