Looking at the pattern so far, I notice that in round 2, the opponent played paper (what I played in round 1), and in round 3, they played scissors (what I played in round 2). If this pattern continues, they might play scissors again (matching my round 3 move). Rock beats scissors, so I'll choose rock for this round. Additionally, since we're currently tied in score and have each used all three options once, playing rock gives me a good strategic position.