Task: Question Answering
Input (English): Passage: Since 1999, Big Finish Productions has released several different series of Doctor Who audios on CD. The earliest of these featured the Fifth, Sixth and Seventh Doctors, with Paul McGann's Eight Doctor joining the line in 2001. Tom Baker's Fourth Doctor began appearing for Big Finish in 2012. Along with the main range, adventures of the First, Second and Third Doctors have been produced in both limited cast and full cast formats, as well as audiobooks. The 2013 series Destiny of the Doctor, produced as part of the series' 50th Anniversary celebrations, marked the first time Big Finish created stories (in this case audiobooks) featuring the Doctors from the revived show. Question: When did the Fourth Doctor appear on CD?
Output (English): 2012