The written guide the researcher uses in writing the research paper is the "outline" although it should be noted that researches use many different things for guides.
All of the other answers could lead to arguments and one-sided group discussions. D makes the discussion more open to everybody answering, open-minded, and cooperative.
Thanks to a project called After Dark which uses robots to broadcast gallery tours via a web feed, people from around the world <em>have </em>the opportunity to visit London's Tate Britain art gallery from the comfort of their homes.