Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
What is 4 Season, when 2 Season is "3 168 673 (2 April 2008)"?

### Inputs:
table_name: table, columns: ['Episode', '1 season', '2 season', '3 season', '4 season', '5 season', '6 season']

### Response:
SELECT 4 season FROM table WHERE 2 season = 3 168 673 (2 april 2008)