The magnetic field in a travelling electromagnetic wave has a peak value of $20\;nT$. The peak value of electric field strength is :

Question

$\begin{array}{1 1} (1) \large\frac{3V}{m} \\ (2) \large\frac{6V}{m} \\ (3) \large\frac{9V}{m} \\ (4) \large\frac{12 V}{m} \end {array}$