Electromagnetic waves travel in a medium which has relative permeability 1.3 and relative permittivity 2.14. Then the speed of the electromagnetic wave in the medium will be

• A

  $13.6\times {10}^6 \mathrm{m}/\mathrm{s}$

• B

  $1.8\times {10}^2 \mathrm{m}/\mathrm{s}$

• C

  $3.6\times {10}^8 \mathrm{m}/\mathrm{s}$

• D

  $1.8\times {10}^8 \mathrm{m}/\mathrm{s}$