Sets A, B, and C are subsets of the universal set U. These sets are defined as follows.
U = {1, 2, 3, 4, 5, 6, 7, 8, 9}
A = {1, 2, 5, 6}
B = {2, 3, 4, 6, 7}
C = {5, 6, 7, 8}
Find (A' ∩ B) ∡ C'. Write your answer in roster form or as ∅.
(A' ∩ B) ∡ C' =