I'm no theoretician, but it seems to me it was careless at best to get caught in such a line. Whatever Anand plays, you can expect him to have done his homework, especially in a World Championship match. He's one of the best prepared players of all time, the 2008 match vs. Kramnik being a case in point, and the finest moment of his career IMHO. So playing ...c6, expecting to take him "a bit out of book", well I guess you take your chances...
That said, I still expect Carlsen to win the match and certainly not to make another similar mistake. At least we'll have a decent fight now, hopefully this should bring out the best in Carlsen and we'll have some great viewing