Question publishing without registration

Question publishing without registration: if some one ask a question then click on submit button, it’s redirecting to registration page, but if they left without registration, question should not be publish, but for me it’s publishing with “0” name.

But what i want is if a person want to ask a question he must be register if he left after submit question, it should not be publish. Can you please tell me is there any option to do this.