Let take three sets A = {1, 2), B = {2, 3} and C = {3, 1}: A ∩ B, B ∩ C and A ∩ C should be non-empty sets. A ∩ B = {2}, B ∩ C = {3} and A ∩ C = {1}
Therefore, A ∩ B, B ∩ C and A ∩ C are non- empty. Intersection of all three sets is null set, A ∩ B ∩ C = ∅.