The results of an election are shown below. Find the winner by plurality, single (top-two) runoff, point system (Borda count), and pairwise comparisons (Condorcet method).   Enter A, B, or C as your answer. The plurality winner is: [Fill in the blank], The single (top-two) runoff winner is: [Fill in the blank], The point system (Borda count) winner is: [Fill in the blank], The pairwise comparisons (Condorcet method) winner is: [Fill in the blank], 多项填空题