Read the excerpt from "a modest proposal."

i profess, in the sincerity of my heart, that i have not the least personal interest in endeavouring to promote this necessary work, having no other motive than the publick good of my country, by advancing our trade, providing for infants, relieving the poor, and giving some pleasure to the rich. i have no children, by which i can propose to get a single penny; the youngest being nine years old, and my wife past child-bearing.

which statement best describes how irony is used in this excerpt?
swift states that he is speaking from “the sincerity in [his] heart.”
swift states that he has an interest in “the publick good of [his] country.”
swift states that the youngest of his children is “nine years old.”
swift states that his “wife is past child-bearing” age.