Which sentence has a parallel structure

According to stephen hawking in the "origin of the universe" lecture, "why are we here" and "where did we come from" are questions that

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?

What do the excerpts have in common? both point out the tragic nature of situations in which children make journeys without their parents. both describe what immigrant children must do to survive when traveling to the united states. both explain why most children want to leave central america without their parents. both indicate the tragic problems and their consequences that children in central america must face.