[unnouinceput]

The only clear and no margin for confusion is the one with "X" vs "check" inside the circle. If that "X" would be red and the check green that would add even more clarification. I hate UI's where I have to click everything first in order to understand what's what, I prefer intuitive design instead.

[seszett]

X is equivalent to a check mark for most people. I think it's mostly an American thing to see an X as meaning "not checked".