The expression of the most probable speed of gaseous molecules is

The expression for the most probable speed of gaseous molecules is $\sqrt{2{\mathrm{k}}_{\mathrm{B}}\mathrm{T}/\mathrm{m}}$

Where, m is the molar mass of the substance, expressed in kilograms, T is the temperature, ${\mathrm{k}}_{\mathrm{B}}$ is the kinetic energy of the molecule.

Hence, the correct option is B