The study shows that wallets with money are more likely to be returned than empty ones, and wallets with both money and a key have the highest return rate.
This suggests people's compassion and empathy play a significant role in their decision to return lost items. The presence of a key likely increases the empathetic response, as it symbolizes personal belongings and potential inconvenience to the owner.
Hence, human compassion drives the honest behavior of returning lost items, especially when a key is involved.
Correct Answer: B