Light is an electromagnetic wave. ls speed in vacuum is given by the expression (All symbols have their usual meaning)

• A

  $\sqrt{{\mathrm{\mu }}_0{\mathrm{\epsilon }}_0}$

• B

  $\sqrt{\frac{{\mathrm{\mu }}_0}{{\mathrm{\epsilon }}_0}}$

• C

  $\sqrt{\frac{{\mathrm{\epsilon }}_0}{{\mathrm{\mu }}_0}}$

• D

  $\frac{1}{\sqrt{{\mathrm{\mu }}_{\mathrm{o}}{\mathrm{\epsilon }}_{\mathrm{o}}}}$