Which has maximum internal energy at $290K$?

The correct option is C Ozone gas
$U=\frac{nfRT}{2}n\to \text{moles}f\to \text{Degree of freedom}R\to \text{gas constant}T\to \text{Temperature}$
We know that degree of freedom is directly related to the atomicity of gas.
Thus, $U$ is directly related to atomicity of gas at a particular temperature.
$\therefore U$ of ozone is maximum.