Quesion about fuel lines in the engine bay
 

So I have been told one of these lines is the fuel supply line, one is the fuel return line, and one is a breather line. So which one is which?

1:?
2:?
3:?

Thanks in advance

http://evanfitch.com/images/fuellines.jpg

1 charcoal canister <~~~~~don't cap this off,it needs to be vented.
2 return
3 supply