If A = {1, 3, 5, 7, 9, 11, 13, 15, 17}, B ={2, 4, ......, 18} and N, the set of natural numbers is the universal set, then (A′∪[(A∪B)∩B′]) is
ϕ
N
A
B
A′∪[(A∪B)∩B′]=A′∪[(A∩B′)∪(B∩B′)]=A′∪[(A∩B′)∪ϕ]=A′∪(A∩B′)=(A′∪A)∩(A′∪B′)=N∩(A∩B)′=(A∩B)′=ϕ′=N