Axisymmetry supplies conserved $p_\theta$ in addition to conserved <energy>. Consequently $\boxed{f=F(H,p_\theta)}$ is a more general <stationary solution>, since both <Argument>[arguments] are constant on every trajectory. Additional independent <Integral>[integrals] may permit still more general distributions. This is a sufficient construction, not a claim that every <stationary distribution> must have exactly these two <Argument>[arguments].

Solution

Past exam of the short options paper shared by Prelims and Parts A and B of the physics course of the University of Oxford / 2017 / S7 / 3 / e / Solution

 Solution (source code)