The Cause of the Pulsations We See in the Light

Multiple Choice

The cause of the pulsations we see in the light from neutron stars is

A) pulsations of its neutrons.
B) motions of electrons within the star.
C) the spinning motion of the star.
D) the in and out pulsations of star's radius, as the star gets rapidly larger and then smaller.
E) Nonsense-- neutron stars do not pulsate.