The 3rd shirt should be completely see-through. This is something that you would normally only wear over a tank-top or another shirt. You should be able to clearly see any color bra under through this shirt. If you're wearing it without a bra, you should be able to clearly see your nipples through it. If you wrote your phone number on your tit, somebody across the room should be able to read it and give you a call (don't worry, you won't actually have to do that).