The reason why it is important that "the story of an Hour" takes place in the nineteenth century is that In the nineteenth century, women were not considered equal to men.
We can see many moments through the story where it is shown with the character's attitude and social interaction that women were not seen as equal to men and that they were supposed to be raised to become housewives and mothers.
The other options are not correct because they don't really represent a nineteenth-century exclusive trait in comparison to nowadays.