Given the tables have been created without foreign keys added, which of the following ALTER TABLE statements would create a foreign key on the category$\_$id in the product table to reference the category$\_$id in the category table?

a$.)$

ALTER TABLE category

ADD CONSTRAINT fk$\_$product

FOREIGN KEY $($category$\_$id$)$

REFERENCES product $($category$\_$id$)$;

b$.)$

ALTER TABLE product

ADD CONSTRAINT fk$\_$product

FOREIGN KEY $($category$\_$id$)$

REFERENCES category $($category$\_$id$)$;

c$.)$

ALTER TABLE product

ADD CONSTRAINT

FOREIGN KEY $($category$\_$id$)$

REFERENCES category $($category$\_$id$)$;

d$.)$

ALTER TABLE product

ADD CONSTRAINT fk$\_$product

FOREIGN KEY category $($category$\_$id$)$

REFERENCES category$\_$id;