Looking at the previous rounds, there appears to be a pattern in the opponent's choices: scissors → paper → rock. If this pattern continues, the opponent might choose scissors in round 4. To counter scissors, I would normally choose rock. However, considering that the opponent might be analyzing my moves as well, they might anticipate me choosing rock and switch to paper instead. In that case, scissors would beat their paper. Additionally, I've only used scissors once so far (in round 1), which resulted in a tie, so the opponent might not expect me to use it again so soon. Given these considerations and the limited pattern data available, I'll choose scissors for round 4.