In an electromagnetic wave travelling in air, the amplitude $E_o$ and $B_o$ of the electric and magnetic fields are related as (here $c$ is the speed of the wave in air)

Question

$\begin {array} {1 1} (a)\;E_o = cB_o & \quad (b)\;E_o = \large\frac{B_o}{c} \\ (c)\;E_o = c^2B_o & \quad (d)\;E_o = B_o \end {array}$