Chances are slight that Brian is a swan. It is almost certain that Mary went to the office. It is probably not the case that Jessica is a mouse.
It is probably not the case that either Jessica is a mouse, or Brian is a swan.
It is probably not the case that either Jessica is a mouse, or Brian is a swan.
It is almost certain that either Jessica is a mouse, or Brian is a swan.
Either Jessica is a mouse, or Brian is a swan.