Character shift in a story is realistic only if there are motives for it and these motives match the general context of the story.
This occurs if there is a sudden/unexpected change in a character's personality or actions.
The key element that makes this shift realistic are reasons or context that cause the character to change.
This character change is realistic because we know Mrs. Sommer is a caring mother who always thinks about her children first. Despite this, it is quite understandable and realistic that for one day she decides to think on her, which is triggered when she buys the pair of stockings.
Note: This question is incomplete because the name of story it refer to is missing; here is the possible story.
Learn more about character shift in: https://brainly.com/question/16663916
#SPJ1