How can the misuse of irony be confusing to readers?

Published in 1849, by was inspired by the writer's experience of being arrested when he refused to pay a $1 poll tax as a protest against the mexican-american war.

Which statement from chamberlain's speech to parliament did the least to support his cause? a. "no doubt i shall have plenty of critics who will say that i am guilty of facile optimism . ." b. "the house will remember that when i last addressed them i gave them some account of the godesberg memorandum . ." c. "therefore, it was essential that we should quickly reach a conclusion . ." d. "the relief that our escape from this great peril of war has, i think, everywhere been mingled in this country with a profound feeling of sympathy . ."

When lawrence saw the posters for the circus hanging on the bulletin board, as he swept up the trimmings at slim's barbershop, he knew he would be taking his little cousins. they loved animals, and he was looking forward to seeing the smiles on their faces as the circus performers amazed them with their stunts. but sweeping up hair clippings didn't pay a whole lot. lawrence spent 45 dollars just getting tickets. but it was worth it to see his cousins' faces. the day finally came and everyone was excited as they walked into that big circus tent. but lawrence soon realized that he and his cousins would be thirsty and hungry. as they sat in their seats, the drink vendor walked by selling beverages. desperately thirsty, lawrence asked him how much a lemonade would cost, and the drink vendor said, "eleven dollars each." lawrence replied, "oh, that's it? just eleven dollars? what a great deal for one cup of lemonade. that's totally worth it." the drink vendor walked away. which type of irony is used?