On August 5, 2008, SCA and Bertelsmann announced that Sony had agreed to acquire Bertelsmann's 50% stake in Sony BMG. Sony completed its acquisition of Bertelsmann's 50% stake in the companies' joint venture on October 1, 2008. The company, once again named Sony Music Entertainment Inc., became a wholly owned subsidiary of Sony Corporation through its US subsidiary SCA. The last few albums to feature a Sony BMG logo were Thriller 25 by Michael Jackson, I Am... Sasha Fierce by Beyoncé, Keeps Gettin' Better: A Decade of Hits by Christina Aguilera, and Safe Trip Home by Dido. A temporary logo was unveiled beginning December 1, 2008. The present logo was unveiled in March 2009.
A permanent logo was unveiled on December 1 of what year? (If the question is unanswerable, say "unanswerable")
unanswerable