The speed of electromagnetic wave in vacuum is given by

• A

  ${\mathrm{\mu }}_0{\in }_0$

• B

  $\sqrt{\left({\mathrm{\mu }}_0{\in }_0\right)}$

• C

  $\frac{1}{\left({\mathrm{\mu }}_0{\mathrm{ϵ}}_0\right)}$

• D

  $\frac{1}{\sqrt{\left({\mathrm{\mu }}_0{\mathrm{ϵ}}_0\right)}}$