Let M and N be two entities in an E-R diagram with simple single vale attributes. R1 and R2 are two relationship between M and N, whereas R1 is one-to-many and R2 is many-to-many. The minimum number of tables required to represent M, N, R1 and R2 in the relational model are .......... (1) 4 (2) 6 (3) 7 (4) 3