Well , then finally we got to watch The Dark Night , which we both really enjoyed . We then walked through the beautiful city of Mainz at 2 am . Afterward , we were talking and nerding out for a few hours - and since Kentrin had to get up at like 8 we just decided to pull an all nighter and sleep late .

Question: Why did they decide to pull an all nighter and sleep late ?
Answer: None of the above choices .They slept late after they talked and nerded out for a few hours .Because they were walking through the city at 2 am .They decided to sleep later after watching the Dark Knight .