Answer:
He is a stone mason.
Step-by-step explanation:
In the short story, "The Cask of Amontillado," the main character Montresor is a mason because he uses bricks and mortar to wall up his enemy alive. Montresor's victim, Fortunato, is a Mason because he identifies himself by gesture and word as member of the Brotherhood of Freemasons:
"He. . .threw the bottle upward with a gesticulation I did not understand.
I looked at him in surprise. He repeated the movement -- a grotesque one.
"You do not comprehend?" he said.
"Not I," I replied.
"Then you are not of the brotherhood."
Montresor, then, pulls out a bricklayer's trowel from under his cloak as proof that he is in fact a "mason."
Have a lovely rest of your day! :)