Looking at the pattern so far, I've won three consecutive rounds by choosing paper, rock, and scissors. My opponent might be expecting me to cycle back to paper for this round (continuing the pattern), and could play scissors to counter that. By choosing rock, I can potentially counter their scissors if they try this strategy. Additionally, after three losses, my opponent may change their approach entirely, making this a good time to play conservatively with rock. Since I have a significant lead (3-0), a strategic defensive play seems appropriate.