Which sentence from "Flight to the South Pole" foreshadows the difficult decision that Admiral Byrd would need to make later in the excerpt?

1. Rather, it was the thought of the "Hump," and how we should fare with it.
2. There were handshakes all around, and at 3:29 o'clock we were off.
3. McKinley had his mapping camera ready for action either on port or starboard side.
4. It was quite warm forward, behind the engines.