The realist art is based on the concrete and real things and places. Its characters are ordinary people with the everyday language used. Its only interest is to represent the recent or contemporary life and events.
Because of that, it has no approval for the romantic way of representing things, since it goes against its believes. Romantic writers are interest in history or legends, with a formal and inflated language, made up, exotic or mysterious settings and extravagant characters. Making so letter D correct, realist writers disapprove romantics for its "fanciful treatment of material".