Which sentences use the rhetorical device of irony？

A、The American dream promised older people that if they worked hard enough all their lives, things would turn out well for them.

B、But what are an individual’s chances for a “good” old age in America, with satisfying final years and a dignified death？

C、And though I’m as leery of certain polls as anyone, this margin of credulity is too wide to be discounted.

D、He stands there, his feet braced, his head high from the soaring mountain of his huge neck, and he wonders where he is.