Final answer:
The correct expression is r > 165 (option A).
Step-by-step explanation:
To win the school art competition, a finalist must receive over 50% of the votes cast by their peers. If 330 students vote and r represents the minimum number of votes a finalist needs to win the competition, we can set up the inequality r > 0.5(330) which simplifies to r > 165.
Therefore, the correct expression is r > 165 (option A).