Hope this helps: an outcome that turns out to be very different from what was expected.
The first and last ones are wrong, because the first one is kind of expected. The parents always want to see their babies when they are born. The metal basin that comes crashing down the stairs is irrelevant.
The nurse not wanting Mr. Button to see his baby is kind of expected, since the baby looks like a 70 year old man. So, I would say the second answer, the baby who is born as a 70 year old. Because that's not expected.
