Table:
text: List of Comedy Central Presents episodes
Episodes
Season 15 (2011)
No_in_Series No_in_Season Performer Appearance Air_Date_
268 1 Tom Segura only 21 January 2011
269 2 Michael Kosta only 21 January 2011
270 3 Sheng Wang only 28 January 2011
271 4 Chelsea Peretti only 28 January 2011
272 5 Chris D`Elia only 4 February 2011
273 6 Nate Bargatze only 4 February 2011
274 7 Hari Kondabolu only 11 February 2011
275 8 Jack Whitehall only 11 February 2011
276 9 Al Jackson only 18 February 2011
277 10 Kyle Kinane only 25 February 2011
278 11 Matt Fulchiron only 25 February 2011
279 12 Mike Vecchione only 4 March 2011

Question: How many cast members appeared on the episodes of Comedy Central Presents on the January 21, 2011 air date?