Which of the following statement(s) is(are) correct about the gas...

Which of the following statement(s) is(are) correct about the gas according to "Kinetic molecular theory"? (i) The mean free path is much higher than the diameter of the gas (ii) The molecules move in straight lines until they colloide (iii) The diatomic gas has a relationship between absolute temperature and root mean square speed ( $\mathrm{V}_{\mathrm{ms}}$ )$as \mathbf{T}=\frac{\mathbf{M V}_{\text {ms }}^2}{\mathbf{9 R}}$ (M-molar mass, R-universal gas constant) (iv) Potential energy of the gas has 100\% contribution towards the total energy of the gas