v₁ and v₂ are the velocities of sound at the same temperature in two monoatomic gases of densities $\mathrm{\rho }$₁ and $\mathrm{\rho }$₂ respectively. If ${\mathrm{\rho }}_1/{\mathrm{\rho }}_2=\frac{1}{4}$ then the ratio of velocities v₁ and v₂ will be 

• A

  1 : 2

• B

  4 : 1

• C

  2 : 1

• D

  1 : 4