In class, the teacher brought a piece of ore for A, B, C 3 students to identify. It's not iron, it's not lead,  A said. It's not iron, it's copper,  B said. It's not copper, it's iron, C said. The teacher concluded: Of the three, one person's two judgments are correct. The other person's two judgments are wrong, and one person's two judgments one-on-one wrong.
Based on the above criteria, this ore is copper is correct.