The given pattern is D because the first line and third line don't rhyme, while the second and fourth do. This is regarding each stanza of the poem.
I know this may start controversy but it's not oppressed if they don't know they're oppressed. But if being abused then let them free yes, but on the terms of being oppressed then no.
The used figurative language is METAPHORE.
As in so many mystery novels, Roger Ackroyd is set in a small, isolated community where everybody knows everybody else. The isolated, close-knit setting 1) suggests that the criminal is someone who everybody knows, and 2) creates a paranoid, suspenseful mood, since the criminal is hiding a big secret from their neighbors. It’s also telling that the owners of the two most “important houses” in town are also the two main victims of the novel.