Let $M$ and $N$ be two entities in an $E-R$ diagram with simple single value attributes. $R_{1}$ and $R_{2}$ are two relationship between $M$ and $N$, where as $R_{1}$, is one-to-many and $R_{2}$, is many-to-many.
The minimum number of tables required to represent $M, N, R_{1}$, and $R_{2}$, in the relational model are ___________.
- $4$
- $6$
- $7$
- $3$