单选题 .  ①In recent decades, scholars of American literature have skillfully revealed authors' simultaneous accommodation and resistance to an increasingly commercialized, capitalized environment during the early nineteenth century. ②Historians of the period have not, however, fully exploited literary criticism, due to the disciplinary boundaries that mark contemporary academic research. ③Few historians have extensive training in critical theory and its specialized languages, and the sheer volume of work in early American history and literature challenges anyone who would master either field, much less both. ④Moreover, historians study people across the nation, but much literary scholarship called "American" actually examines works produced in northeastern states. ⑤And historians usually study the operations of capitalism in its details, while literary critics produce a generalized picture of literary commodification.12.  As discussed in the passage, the literary scholars and the historians differ in which of the following ways? ______