One Newly Discovered Type of Neutron Star Is the "Rotating

One newly discovered type of neutron star is the "rotating radio transient," which occasionally emits a very brief burst of intense radio radiation. What is the BEST explanation, at present, for this phenomenon?

A) Rotating radio transients are very young neutron stars, and they emit radio radiation in response to a "settling down" deep in their interiors.
B) Rotating radio transients are very old neutron stars. They have cooled off until their temperatures are low enough to emit radiation in the radio range.
C) Rotating radio transients are neutron stars in eclipsing binary systems, and the output of radio radiation is periodically eclipsed by the companion.
D) Rotating radio transients are pulsars whose rotation rate has slowed down to about one rotation every 0.4 to 10 seconds.