Based on the previous rounds, the opponent played rock in round 1 and paper in round 2. This could suggest a cyclic pattern where the opponent might choose scissors in round 3, or perhaps they’re copying my previous move (paper), in which case scissors would beat paper. Given these possibilities, choosing scissors ensures that if he copies (and plays paper) I win, and if he cycles (and plays scissors) I tie. Thus, scissors is the safest and most advantageous move here.