Ultrasonic, Infrasonic and audible waves travel through a medium with speeds ${\mathrm{V}}_{\mathrm{u}},{\mathrm{V}}_{\mathrm{i}}$ and ${\mathrm{V}}_{\mathrm{a}}$ respectively, then

• A

  ${\mathrm{V}}_{\mathrm{u}},{\mathrm{V}}_{\mathrm{i}}$ and ${\mathrm{V}}_{\mathrm{a}}$ are nearly equal

• B

  ${\mathrm{V}}_{\mathrm{u}}\ge {\mathrm{V}}_{\mathrm{a}}\ge {\mathrm{V}}_{\mathrm{i}}$

• C

  ${\mathrm{V}}_{\mathrm{u}}\le {\mathrm{V}}_{\mathrm{a}}\le {\mathrm{V}}_{\mathrm{i}}$

• D

  ${\mathrm{V}}_{\mathrm{a}}\le {\mathrm{V}}_{\mathrm{u}}$ and ${\mathrm{V}}_{\mathrm{u}}\approx {\mathrm{V}}_{\mathrm{i}}$