D. How does a rollercoaster's energy keep passengers from falling out of their seats? This would be the correct answer because it's a question going into the works of how rollercoasters are made to keep their passengers safe while the ride is going. A wouldn't be correct, because they're asking about which parks are known for having the safest rollercoasters, and not why it is safe. Just eliminate all the answers that don't make sense until you narrow it down to the one that does make sense. I hope this helps! :)