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

How do pip's feelings of guilt in chapter 6 fluctuate? a. he feels both guilty and exhilarated by the opportunity to interact with a convict. b. he doesn't feel any true guilt, but rather fear that he will be caught and self-loathing that he stole. c. he feels guilty, but only until the convict is found. d. he feels guilty for lying to joe, but not for stealing from mrs. joe, because he doesn't love her.