The classic prisoner's dilemma involves two suspects, A and B, who are arrested by the police. Because the police have insufficient evidence for conviction on a key charge, they place the prisoners in isolation and offer each of them the following deal: If one testifies for the prosecution against the other and the other remains silent, the betrayer goes free and the silent accomplice receives a 20-year sentence. If both stay silent, both prisoners are sentenced to only six months in jail on a minor charge. If each betrays the other, each receives a five-year sentence. Each prisoner must make the choice of whether to betray the other or to remain silent. Neither prisoner knows for sure what choice the other prisoner will make.