HELP PLZ i think it’s a or b but not sure

Wha is the best example of a storys historical context? a. the way the plot is eventually resolved b. the genre that the story belongs to c. the theme that the story explores d. the cultural beliefs of the characters

This dust was once the manthis dust was once the man, gentle, plain, just and resolute, under whose cautious hand, against the foulest crime in history known in any land or age, was saved the union of these states walt whitman who is "the man" the dust now represents? the narrator a criminal whitman lincoln

Which of the number is main idea? i need this quick.