"This is your last lesson before your OWLs, so I'll let you study here for the remaining time period, or you can scamper off. Utilize your time wisely. If you choose to study in this classroom, you can do so with any subject. You can ask me anything as well, but depending on the subject, I won't be much use to you. I am not good with Divination, Care of Magical Creatures, and Muggle Studies. The rest I know fairly well." Vader would give them that option before he would dismiss them to do what they wanted.
Assignment: Attendance post.
Assignment: Attendance post.