If X1, X2, X3, _ _ _ _ _, XN are the domains in a relational database model, then the relation (table) is a subset of which of the following?
1
X1 ∪ X2 ∪ X3 ∪ _ _ _ _ _ ∪ XN
2
X1 + X2 + X3 +_ _ _ _ _ + XN
3
X1 ∩ X2 ∩ X3 ∩ _ _ _ _ _ ∩ XN
4
X1 × X2 × X3 × _ _ × XN
5
Question Not Attempted