Which statement is NOT CORRECT?

a$.$ The ER model does not enforce that a supplier can only have purchase orders outsunding for products he$/$the can actually supply.

b According to the ER model, there can be fuppliers that fupply no products and have no purchase orders outstanding.

c According to the ER model, a suppler cannot have more than $1$ address.

d$.$ The ER model has both weak and evistence depandent entity typt$2.$