An electron enters with a velocity $\overrightarrow{v} =v_0 \hat i$ into a cubical region (faces parallel to coordinate plane ) in which there are uniform electric and magnetic fields. The orbit of the electron in front to spiral down inside the cube in plane parallel to the x-y plane . Suggest a configuration of fields $\overrightarrow{E}$ and $\overrightarrow{B}$ that can lead to it.

Question

$\begin{array}{1 1} \overrightarrow{E}= E_o\hat j \\ \overrightarrow{E}=E_0 \hat k \\ \overrightarrow{E}= E_0 \hat i \\ none\;of\; the \;above \end{array} $