29. The electric field of a sinusoidal electromagnetic wave in vacuum is given: $E_x = E_y = 0$,
$E_z = E_0 cos(ky - \omega t)$. The magnetic field of this wave is
A. $B_x = B_y = 0$, $B_z = B_0 \times cos(ky - \omega t)$
B. $B_x = B_y = 0$, $B_z = B_0 \times sin(ky - \omega t)$
C. $B_y = B_z = 0$, $B_x = B_0 \times cos(ky - \omega t)$
D. $B_y = B_z = 0$, $B_x = B_0 \times cos(ky + \omega t)$
E. $B_x = B_z = 0$, $B_y = B_0 \times cos(ky + \omega t)$