The most probable velocity of the molecules is given by ( $\mathrm{m}$ is mass of a molecule)

We know that most probable velocity is defined as velocity possessed by the maximum fraction of gaseous molecules at a particular time.

Most probable velocity = $\sqrt{\frac{2\mathrm{RT}}{\mathrm{m}}}$

And, when we write it in terms of Kinetic energy most probable velocity = $\sqrt{\frac{2\mathrm{KT}}{\mathrm{m}}}$

Hence, Option(C) is the answer.