Based on the opponent's pattern, they heavily favor paper (5 out of 9 rounds). However, since this is the final round and I'm ahead 2-1, I need to avoid losing more than I need to win. The opponent might anticipate I'll choose scissors to counter their paper tendency, and counter with rock (as they did in round 8). By choosing rock, I can at worst tie against their rock, win against their scissors, and only lose if they choose paper. Given their history, this provides a balanced approach that prioritizes not losing the match.