If a database designer follows the guideline that every determinant should be a candidate key, the resulting tables will minimally be in

Boyce Codd Normal Form  BCNF

Explanation:

Boyce-Codd normal form is a special case or extension of 3NF (Third Normal Form). The anomalies with which 3NF cannot deal are dealt in BCNF. A relation is in BCNF if it is in 3NF and iff X is the superkey for every functional dependency i.e X->Y. So for a relational schema to be in BCNF every determinant must be a candidate key. No redundancy exists in BCNF

Lets take an example of a database schema:

Person( id#, name, address)  

The only Functional Dependency is id# -> name, address  

Here id# is a key,  Hence Person is in BCNF

the answer is d underlined.