A- Based on the passage, one of the themes in the passage is the struggle between sanity and madness.
C- The theme highlights the narrator's obsessive reasoning, which leads him to believe he is rational despite his violent thoughts and actions.
E- For example, in the passage, the narrator insists, “But you should have seen me. You should have seen how wisely I proceeded—with what caution—with what foresight—with what dissimulation I went to work!”
S- This shows that the narrator deeply believes in his own sanity and cunning, despite the horrific nature of his intentions and actions toward the old man because of the "vulture eye."
In conclusion, Poe illustrates the thin line between sanity and madness through the narrator's meticulous planning of murder while simultaneously claiming his rationality.