This experiment used a between-subjects design, meaning that the experiment compared different groups of participants against each other. the control and experimental groups differ?

The experimental and control groups had to choose between different sets of tasks.
The experimental group could have their choice of ice cream for completing the long task, but the control group could not.
The experimental group received points that they redeemed for ice cream, whereas the control group received ice cream directly.
The experimental group had to wait a week before receiving their ice cream, but the control group received it immediately.