Read this excerpt from "the gun"

and behind came more carts, some with relays, some with firing controls, some with tools and parts, screws and bolts, pins and nuts. the final one contained atomic warheads.

the carts lined up behind the first one, the lead cart. the lead cart started off, across the frozen ground, bumping calmly along, followed by the others. moving toward the city.

to the damaged gun.

with these final lines of "the gun," the reader has more knowledge about what will happen in the future than do the characters in the story. which of these rhetorical devices has he used in the ending of his story?

a. euphemism
b. dramatic irony
c. hyperbole
d. sarcasm