Consider the sound wave travelling in ideal gases of He, $$CH_4$$, and $$CO_2$$. All the gases have the same ratio $$\dfrac{p}{\rho}$$, where P is the pressure and $$\rho$$ is the density. The ratio of the speed of sound through the gases $$v_{He} : v_{CH_4} : v_{CO_2}$$ is given by

A

$$\sqrt{\dfrac{7}{5}} : \sqrt{\dfrac{5}{3}} : \sqrt{\dfrac{4}{3}}$$

B

$$\sqrt{\dfrac{5}{3}} : \sqrt{\dfrac{4}{3}} : \sqrt{\dfrac{7}{5}}$$

C

$$\sqrt{\dfrac{5}{3}} : \sqrt{\dfrac{4}{3}} : \sqrt{\dfrac{4}{3}}$$

D

$$\sqrt{\dfrac{4}{3}} : \sqrt{\dfrac{5}{3}} : \sqrt{\dfrac{7}{5}}$$