I'd like to get a great answer with explain how did you find tit for tat, tit for two tats and Grim

I have the answer but I dont Know how he did it.

Iterated Prisoner's Dilemma Co-operate. Defect. Tit for Tat - co-operate first, then copy opponent. - co-operate twice, then copy opponent. Grim - co-operate but if opponent defects, then always defec Produce a table of outcome over 5 games. \begin{tabular}{|l|l|l|l|l|l|l|} \hline & Co-op & defect & Tit-tat & Tit-2tats & Grim & \\ \hline Co-op & (15,15) & (0,25) & (15,15) & (15,15) & (15,15) & 60 \\ \hline defect & (25,0) & (5,5) & (9,4) & (13,3) & (9,4) & 61 \\ \hline Tit-tat & (15,15) & (4,9) & (15,15) & (15,15) & (15,15) & 64 \\ \hline Tit-2tats & (15,15) & (3,13) & (15,15) & (15,15) & (15,15) & 63 \\ \hline Grim & (15,15) & (4,9) & (15,15) & (15,15) & (15,15) & 64 \\ \hline \end{tabular}