Let R and S be the relation respectively: Relation R: A B C Relation S: B C D 1 2 3 2 3 4

Let R and S be the relation respectively: Relation R: A B C Relation S: B C D 1 2 3 2 3 4 6 7 8 2 3 5 The number of tuplesthat the result of the expression R ∞ S (Here is the natural join of relations R and S) is

A．3

B．4

C．6

D．9