This question is incomplete. Here is the complete question:
Which sentence signals a plot twist about halfway through the story?
“The kid with the earring starts screaming, ‘Goldfish, goldfish.'”
“‘No reason to take him to the hospital anyway,' says the goldfish.”
“Sergei . . . tells the kid, it's nothing, just a regular goldfish.”
“Sergei understands the boy . . . came . . . to snatch Sergei's fish.”
Answer:
The correct answer is “‘No reason to take him to the hospital anyway,' says the goldfish.”
Explanation:
A plot twist is a radical and unexpected turn of events that occurs suddenly for the viewer and that has enough relevance to change the fate of the protagonists of the narrative who suffer from it.
In short, and in simpler words, a plot twist takes place when there is an event that no one expected and that makes a 180 degree turn to what had happened previously.
In this case, it would be the fact that Sergei does not want to use his last wish because he does not want to let the goldfish go free.
The guy was waiting for christoper Columbus at the train station
