Final answer:
The closest match for the average audience size during the 2012-2013 season of NCIS on CBS, based on the record from January 11, 2011, is 20 million viewers. So, the answer is B) 20 million.
Step-by-step explanation:
The student has asked about the average audience size for the television show NCIS on CBS during the 2012-2013 season. Based on the information provided, during a specific episode on January 11, 2011, NCIS drew an audience of 21.93 million viewers. This figure is indicative of the show's popularity, but it doesn't exactly match the choices given for the 2012-2013 season. Considering the options provided and that television networks, including CBS, traditionally have large audiences for their prime-time shows, the closest match to the provided figure would be B) 20 million. Hence, the answer would be B) 20 million.