You know what I mean. Now sure, professional historians & anthropologists may have moved past that, but colloquially the term 'Caucasian' is still treated as synonymous with 'white' generally around here.

Anyway, doesn't change my point, which is that MLK having white ancestry is vastly likelier than Cleopatra having a drop of sub-Saharan blood in his her family tree going back to the very first Ptolemy. In fact it's not even likely but certain; following even a few pages on Wikipedia is enough to lead one to proof (by way of both research done by MLK's own relatives and DNA testing) that one of MLK's ancestors was an Irishman.