The Pulsed Nature of the Radiation at All Wavelengths That

The pulsed nature of the radiation at all wavelengths that is seen to come from a pulsar is produced by

A) the rapid pulsation in size and brightness of a small white dwarf star.
B) the rapid rotation of a neutron star that is producing two oppositely directed beams of radiation.
C) the mutual eclipses of two very hot stars orbiting in a close binary system.
D) extremely hot matter that is rapidly orbiting a black hole just prior to descending into it.