user: ### NOW ANSWER:
Question: What is 4 Season, when 2 Season is "3 168 673 (2 April 2008)"?
Columns: ['Episode', '1 season', '2 season', '3 season', '4 season', '5 season', '6 season']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['1', '2 585 169 (5 September 2007)', '3 077 507 (5 March 2008)', '2 362 818 (3 September 2008)', '3 145 066 (3 March 2009)', '3 299 051 (3 March 2010)', '3 074 536 (2 March 2011)']
SQL:

assistant: SELECT "4 season" FROM "Table" WHERE "2 season" = '3 168 673 (2 April 2008)';