The correct option is
C (A×B)∪(B×A)=(A×B)∪(B×C)(A×B)={(1,1),(1,2,),(2,1),(2,2),(3,1),(3,2)}
(B×A)={(1,1),(1,2),(1,3),(2,1),(2,2),(2,3)}
(B×C)={(1,2,),(1,3),(2,2),(2,3)}
(C×B)={(2,1),(2,2),(3,1)(3,2)}
(A×C)={(2,1),(2,2),(2,3),(3,1),(3,2),(3,3)}
(C×A)={(2,1),(2,2),(2,3),(3,1),(3,2),(3,3)}
∴(A×B)∪(B×A)={(1,1),(1,2),(2,2)(3,1)(3,2),(1,3),(2,3)}
∴(A×B)∪(B×A)=(A×B)∪(B×C)