We have seen that the generation of magnetic fields requires both a rapid rotation and a fluid interior for the flow of currents of charged particles. But neutrons are electrically neutral. So how can a neutron star generate a magnetic field?
A) Neutrons in the neutron degeneracy situation within a neutron star acquire an electric charge.
B) Because the neutrons in a neutron star flow through a superconducting medium, they do not need to carry an electric charge in order to constitute a current.
C) The enormous amounts of friction which degenerate neutrons experience cause electric charges to build up on their surfaces, like static electricity.
D) Neutron stars actually contain some protons and electrons, and these carry the electric currents.