Another newbie question: Let’s say PCs are in a room and there are no threats around.

Another newbie question: Let’s say PCs are in a room and there are no threats around.

Another newbie question: Let’s say PCs are in a room and there are no threats around. No trap, no monsters etc. There’s a rope in the ceiling, connected to a cage, and to reach the cage a PC needs to hit the rope with an arrow. Which move to trigger? Defy danger? If so what are the options? And what’s the danger, lose lots of arrows? And what if PC rolls 7-9? Or trigger any other move?