When does Fortunato first realize that Montresor plans to harm him?
a. when they begin their descent into the vault
b. when he sees the mound of bones on the floor
c. when Montresor chains him to the granite
d. when Montresor walls up the opening
d. when Montresor walls up the opening
The correct answer is d. when Montresor walls up the opening.
To determine when Fortunato first realizes that Montresor plans to harm him, let's analyze the events in Edgar Allan Poe's story "The Cask of Amontillado."
In the story, Fortunato accompanies Montresor to the catacombs to taste a rare wine called Amontillado. As they descend into the vaults, Fortunato becomes increasingly drunk. Montresor then chains Fortunato to the granite, preventing him from escaping. However, it is not mentioned whether Fortunato realizes Montresor's true intentions at this point.
The moment when Fortunato first understands that Montresor intends to harm him is revealed when Montresor walls up the opening. This is indicated in the final lines of the story, where Montresor explains that Fortunato's desperate cries for mercy could be heard from behind the newly constructed wall.
Therefore, the correct answer is d. when Montresor walls up the opening.