The electric field of a monochromatic plane wave travelling in a lossless isotropic and homogenous medium is given by
\[ \vec{E}(z,t)=E_0\left[\hat{x}\cos(\omega t-kz)+\hat{y}\sin(\omega t-kz)\right] \]
in a right-handed orthogonal co-ordinate system.
Which of the following is the correct polarization of the electromagnetic wave?