Q: Of the known supernova progenitor candidates, which star is the closest to us?

A: That would be Spica, the brightest star in Virgo. It is 260 light years away. Betelgeuse is 425 light years distant making it the fifth closest and Eta Carinae, possibly the next supernova in our part of the galaxy, is 7000 light years from us. (“Death From the Skies”, Phil Plait, pg. 311)