Definition: This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.
Input: Passage: TCM's film content has remained mostly uncut and uncolorized (with films natively filmed or post-produced in the format being those only ones presented in color), depending upon the original content of movies, particularly movies released after the 1968 implementation of the Motion Picture Association of America's ratings system and the concurrent disestablishment of the Motion Picture Production Code. Because of this, TCM is formatted similarly to a premium channel with certain films particularly those made from the 1960s onward sometimes featuring nudity, sexual content, violence and/or strong profanity; the network also features rating bumpers prior to the start of a program (most programs on TCM, especially films, are rated for content using the TV Parental Guidelines, in lieu of the MPAA's rating system).
Output:
In what year did TCM introduce its rating system?