3.
what is ironic about the pledge the rioters make in these lines of “the pardoner's tale”?

they made their bargain, swore with appetite. / there three, to live and die for one another / as brother-born might swear to his born brother.

they really are brothers but have forgotten.
they have only just met.
they do not realize that death is listening.
they later plot to kill one another to get a larger share of the gold.