An electro magnetic wave travels in vacuum along z direction $\overrightarrow{E}=(E_1 \hat i +E_2 \hat j) \cos (kz- wt)$ Choose the correct option from the following

Question

$\begin{array}{1 1} \text{The given electro magnetic field is circularly polarized} \\ \text{The given electro magnetic wave is plane polarized} \\ zero \\ \text{none of these} \end{array}$