CREATE TABLE table_47745 ("Series Sorted" TEXT, "Title" TEXT, "Doctor" TEXT, "Featuring" TEXT, "Released" TEXT)

What is the series sorted value for the episode released December 2009?
SELECT "Series Sorted" FROM table_47745 WHERE "Released" = 'december 2009'
SELECT "Series Sorted" FROM "table_47745" WHERE "Released" = 'december 2009'