Answer:
Since we are to choose only what in inferred in the story, the correct option is number 2. One reason Montresor is wearing a costume is to be sure no one recognizes him when he is walking back to his house with Fortunato.
Explanation:
"The Cask of Amontillado" is a short story by Edgar Allan Poe. The narrator is Montresor, a man who wants revenge against Fortunato. <u>It is clearly stated at the beginning of the story that Fortunato has offended Montresor</u>:
<em>THE thousand injuries of Fortunato I had borne as I best could, but when he ventured upon insult I vowed revenge. </em>
Therefore, number 6 is eliminated. <u>Since it is carnival, Fortunato is wearing a costume:</u>
<em>He had on a tight-fitting parti-striped dress, and his head was surmounted by the conical cap and bells.</em>
We can eliminate number 1 with that information. However, it is not stated anywhere that Montresor was wearing a costume with the purpose of disguising himself. So, we should check number 2 as an inference.
<u>Montresor leads Fortunato to the catacombs and gives him wine to keep him drunk:</u>
<em>We came at length to the foot of the descent, and stood together upon the damp ground of the catacombs of the Montresors. [...]</em>
<em>Here I knocked off the neck of a bottle which I drew from a long row of its fellows that lay upon the mould.
</em>
<em>"Drink," I said, presenting him the wine.</em>
We can, thus, eliminate numbers 4 and 8. We can also eliminate number 5,<u> since the narrator clearly states the time:</u>
<em>It was now midnight, and my task was drawing to a close. </em>
Finally, we can eliminate number 3 as well. <u>Fortunato went to the catacombs with Montresor because he was a proud man when it came to knowing wines. He was jealous of the possibility that Luchresi would be the one tasting the Amontillado:</u>
<em>He had a weak point -- this Fortunato -- although in other regards he was a man to be respected and even feared. He prided himself on his connoisseurship in wine.</em>
<em>"Let us go, nevertheless. The cold is merely nothing. Amontillado! You have been imposed upon. And as for Luchresi, he cannot distinguish Sherry from Amontillado."</em>
