Answer:
The setting that an author would most likely use to show that the protagonist is struggling to survive against the harsh realities of nature is "A small town in Kansas where tornadoes threaten the townspeople"
Step-by-step explanation:
If an author wants to set the plot in a setting where the characters have to deal with nature a tornado would be a natural conflict to create conflict, the other given options are social or referent to work conflicts where natures does not have any kind of intervention, then option C is the only one that includes nature in it.