Analyzing the opponent’s past moves shows a pattern: after he switches to scissors (as in rounds 5 and 9 following a rock), he tends to switch to paper. Although his most frequent move overall is rock (4/9 rounds), his immediate history (rock in round 8 followed by scissors in round 9) suggests he may now play paper in round 10. Scissors beats paper, so I choose scissors to maximize the chance of winning the final round and tying the game overall.