A of course, because it indicates just right that Diane says that. All the others , aren't in order and don't really comprehend.
It depends. In most cases emails kind of have a professional stigma following them and are sent to ask questions or to gain information or inform the receiver so it’s best presented in a formal way.
In other cases such as a letter to a friend it can be as informal as the writer would like. Overall though I would say False, emails require professionalism.
