You missed one option: none of these. And that’s what I vote for.
I can’t vote black duck until I know what it is. Briefcase? Don’t want. Smuggle points are better.
Tranquilizer gun might be OP’d. Not sure I’d want that. If they would wake up from it like how Assassins Creed Black Flag and Origins does, then it would be fine, I guess. But still not sure I’d want that in hitman.