Posted by duck on May 29, 2013; 2:16am URL: http://discussion-forum.276.s1.nabble.com/Conceptual-Doubts-from-Q-21-60-DSE-2011-tp7581391p7581424.html
29) Its given in the question that the society and the empty set both are tribes.
And by definition :complement of a tribe is a club. So, society and empty sets are club as well.