The three persons A. B, and C sell their products. One of the three products is a counterfeit product, and the other two are genuine products. A said: "My product is a genuine product, B's product is a counterfeit product"; B said: "My product It's a genuine product, and C's product is a counterfeit product "; C said," B's product is a genuine product, and A's is a counterfeit product. "It is known that one of the three persons A. B, and C is true, one One bit is true, one is false, and one is both false. So who is selling counterfeit goods? ['A.', 'B.', 'C.', 'Unsure.']