The velocity at which a sinusoidal signal of $$ 10^9 rad/s$$ travels down loss-less transmission line for which $$ L = 0.4 \mu H/m$$ and $$ C = 40 pF/m is

A

$$ 2.36 \times 10^8 m/s $$

B

$$ 2.5 \times 10^8 m/s $$

C

$$ 5 \times 10^9 m/s $$

D

$$ 4.5 \times 10^9 m/s $$