If the Electric Field in a Plane Electromagnetic Wave Is $\omega$

If the electric field in a plane electromagnetic wave is along the y axis and its component is given by E_msin(kx + $\omega$ t) , in SI units, then the magnetic field is along the z axis and its component is given by:

A) (E_m/c) cos(kx + $\omega$ t)
B) -(E_m/c) cos(kx + $\omega$ t)
C) -(E_m/c) sin(kx + $\omega$ t)
D) E_mcos(kx + $\omega$ t)
E) (E_m/c) sin(kx + $\omega$ t)