Why did shakespeare's noble characters speak in iambic pentameter while commoners spoke mainly in blank verse or prose?

In which of the following excerpts from "the yellow wall paper" does author charlotte perkins gilman seem to mock the romantic belief in the supernatural? a. a colonial mansion, a hereditary estate, i would say a haunted house, and reach the height of romantic felicity—but that would be asking too much of fate! b. there is a delicious garden! i never saw such a garden—large and shady, full of box-bordered paths, and lined with long grape-covered arbors with seats under them.c. the color is repellent, almost revolting; a smoldering unclean yellow, strangely faded by the slow-turning sunlight.d. then i peeled off all the paper i could reach standing on the floor. it sticks horribly and the pattern just enjoys it!