Answer:
The author uses the lines to present a character versus self conflict.
Based on this excerpt, this stage of the plot is most likely to occur in the exposition.
Explanation:
In the text presented above, we can see an example of a conflict known as Character Versus Self. This conflict occurs when the character in the story is confronted by his own thoughts, which seem to attack him and weaken him. In this kind of conflict, the character feels confused and disturbed by his own mind.
In this excerpt, we are presented with important information about the story, which will allow us to better understand the entire narrative. In this text we are introduced to the characters and the main points of the plot. We know that one of the characters has a psychological disorder, due to a strange eye of an old man and that this disturbance will make him kill this old man. This moment, where the main points of the story are presented to the reader, is called an "exhibition."