Answer: Option C
:
C
The equipartition theorem postulates - each degree of freedom contributes an energy equal to $\left(\frac{1}{2}\right)kT$ to the total internal energy of a molecule, depending on the temperature T. Let's count the number of degrees of freedom for an $O_2$ molecule.

(1) Possible directions of translational motion are the three axes, x, y and z. Thus, number of translational degrees of motion = 3.
(2) Given the negligible size of the atoms, rotation about the bond-axis will not be significant. It can only rotate about the two axes shown (perpendicular to the bond-axis). Thus number of rotational degrees of motion = 2.
Therefore, according the equipartition theorem,
(i) Translational Kinetic energy, $K_{Tr}=\frac{3}{2}kT$,
(ii) Rotational Kinetic energy, $K_{Rot}=kT$.
Clearly, $K_{Tr}$ > $K_{Rot}$.