Which of the Following Presentation Situations Is Best Suited for Impromptu

Which of the following presentation situations is best suited for impromptu delivery?

A) As you walk into a conference room, your boss asks you to summarize the status of a project you are working on.You didn't intend to make a presentation today.
B) You will be conducting a workshop for your coworkers on how to use the company's new and improved email system.You have a month to prepare for the workshop.
C) Because of your great success, you have been invited to be the commencement speaker at your former high school's graduation ceremony.The local newspaper will print a copy of the address the day after the ceremony.
D) None of the above is suited for impromptu delivery.
E) All of the above are suited for impromptu delivery.