You are on an island with two tribes. One tribe always tells the truth, and the other tribe always lies. You meet three individuals from the island: A, B and C. Each individual belongs to one of the tribes. You ask each of them the same question: "Is B a truth-teller?"
A says, "Yes, B is a truth-teller."
B says, "No, I am not a truth-teller."
C says, "B is a liar."