A plane wave with a frequency of 3 GHz is propagating in an unbounded medium with relative permittivity $$ε_r = 6$$ and permeability $$\mu_r = 1.5$$, the phase velocity for this wave in this medium is

A

$$1 \times 10^8$$ m/s

B

$$2 \times 10^8$$ m/s

C

$$3 \times 10^8$$ m/s

D

$$1.5 \times 10^8$$ m/s