He is using Parallelism, don't let the quiz fool you.
The delivery technique Marcus is using while delivering a speech verbatim from a teleprompter is manuscript delivery.
So the text he is reading is called a manuscript, and he is delivering it in front of cameras or people. Verbatim means word for word - so he is reading everything that is written in the text. This is a common method of reading text during news on TV, for example.
Answer: "Casca joins the conspiracy because Cassius uses various means to manipulate his emotions."
