A={2,4,6,8,10} and B={1,3,5,7,9}
then, A∪B={1,2,3,4,5,6,7,8,9,10}
⇒(A∪B)′=∅
If universal set U = {1, 2, 3, 4, 5, 6,7, 8, 9, 10}, A = {2, 4, 6, 8}, then Ac is: