If r is a relation in relational data model and a1,a2,..an are the attributes of relation r, what is the cardinality of r expressed in terms of domain of attributes?
(a) |R|<=|dom(A1)X dom(A2)..dom(An)|
(b) |R|>=|dom(A1)X dom(A2)..dom(An)|
(c) |R|=max(|dom(A1)|,|dom(a2)|,..|dom(An)|)
(d) |R|=min(|dom(A1)|,|dom(a2)|,..|dom(An)|)