Which of the following might provide an explanation for the popularity of hand-in portraits that would satisfy the author of the passage? A. An eighteenth-century English etiquette manual discussing the social implications of the "hand-in" stance B. A comprehensive catalogue of eighteenth-century English portraits that showed what proportion of portraits depicted gentlemen in the "hand-in" stance C. A passage from an eighteenth-century English novel in which a gentleman considers what stance to adopt when his portrait is painted