The Great Breakthrough in Understanding the Nature of Pulsars Was

Multiple Choice

The great breakthrough in understanding the nature of pulsars was the:

A) discovery of a pulsar in the middle of the Crab Nebula.
B) realization that pulsars were found only in the galactic plane.
C) connection between pulsars and variable stars.
D) discovery that all pulsars have periods that are multiples of a universal pulsar period.