A Binary System Is Formed with a Neutron Star and Another

A binary system is formed with a neutron star and another star that has overflowed its Roche lobe. How does the detection of this binary differ from the detection of an isolated neutron star?

A) The outer layers of the larger star envelop the neutron star, so only the spectrum of the larger star is detected.
B) This binary may emit intense X-rays while an isolated neutron star emits radio waves.
C) The interaction of the larger star with the neutron star may slow the neutron star's rotation to the point where it no longer rotates. One then sees a steady radio beam rather than the series of pulses that the lighthouse model predicts for an isolated neutron star.
D) The spectrum of the larger star swamps the spectrum of the neutron star, thus showing a standard thermal blackbody spectrum. An isolated neutron star produces a nonthermal radiation spectrum.