Suppose you have a CUSTOMERS table that contains customer contact information.

Which of the following is an example of a constraint that might be useful to set up for that table?

a$.)$

Creating a one$-$to$-$one relationship between the CUSTOMERS table and the ORDERS table

b$.)$

Requiring that entries in the zip code field be either five or nine digits long

c$.)$

Requiring a relationship between the CUSTOMERS table and the ORDERS table

d$.)$

Automatically deleting any records in the CUSTOMERS table that do not have any orders in the ORDERS table