For a Question to reach the final Rejected state will depend on the number of Reviewers assigned for the Question.
As a Reviewer, if you feel the Question does not meet the requirements, then you should reject the Question. On clicking the Reject button, a dialog box will ask you to enter a mandatory explanation for the rejection.
If there is more than one Reviewer, the rejection process will need to meet the rejection criteria decided for the Question.
For example, if there are two Reviewers for a Question, a minimum of 2 Reviewers (or as decided) will be required to reject the Question.
The user rejecting the Question will get the popup window to choose the state, if the state of the Question is going to be changed.
If there are more than two Reviewers for a Question, the first Reviewer will not get the dropdown option to choose where to send the Question.