Definition:Prisoner's Dilemma

Definition
The Prisoner's Dilemma is an instance of a class of games whose mechanics are as follows:

Two suspects in a crime are interviewed separately.

If they both confess, they will be sentenced to $3$ years in prison.

If only one of them confesses, he will be freed and used as a witness against the other, who will then receive a sentence of $4$ years.

If neither one confesses, they will both be sentenced for lesser crime, and each will spend $1$ year in prison.

Payoff Table
The payoff table of the Prisoner's Dilemma is as follows: