Bear in mind that Creative Commons is a facility for the copyright holder to standardise their selective granting of permission (from the public’s suspended right to copy), whereas copyleft is a means of emancipation (restoring the public’s right to cultural liberty in an author’s published art and its published derivatives).

They are distinct philosophies. I wouldn’t attempt to locate Copyleft within the panoply of CC licenses. Instead one can estimate the CC license that has the greatest proximity to copyleft, i.e. CC-SA.

Copyleft attempts to neutralise copyright via a conditional license for the liberation of the public, whereas CC licenses simply modulate the constraints of copyright according to the author’s self-interest.