Answer:
The correct answer is option C.
Step-by-step explanation:
The main conflict is the one that HELPS ADVANCE THE PLOT OF A STORY.
All stories have a protagonist and an antagonist. Between these characters, there are always rivalries leading to create internal conflicts to be solved. Moreover, the readers get engaged and usually take part for the protagonist. Without a main conflict, the story would not have any purpose to be told.
For example, in "The Streetcar Named Desire" by T. Williams is the conflict between Blanche and Stanley what helps advance its plot.