For sets A and B, (A∪B)′∪A′∩B equals
A'
B'
A
None of these
(A∪B)′∪A′∩B=A′∩B′∪A′∩B=A′∪A′∩A′∪B∩B′∪A′∩B′∪B=A′∩A′∪B∩B′∩U=A′∩A′∪ϕ∩U=A′∩A′∩U=A′∩U=A′