Update: The tombstone sans the text is from a political blog by Andy Barefoot, who provides a tombstone generator. The page states "create your own poster", which might or might not state a copyright statement for a generated poster. The sentence eMail is where knowledge goes to die gets attributed to Bill French, but might have many parents. "Stop sending, start sharing" is my sentence, but I'm sure someone possibly has said that before (I just didn't come across it).
Now it is anybody's guess if the combination of all these constitutes a) a new asset in its own right, b) (re)use of the stated items is covered by fair use or a license - c) that the necessity to think about that is plain mad.
If your conclusion is: It constitutes an original art work by me, then the Creative Commons License as stated below would be in effect.