A correct option is option (a). The strongest normal form that R=AB is in is not known since we don't know the set of functional dependencies
What are functional dependencies?
An association between two attributes, often the PK and other non-key properties in a database, is known as a functional dependency (FD). If the value of attribute X (often the PK) impacts the value of attribute Y in a unique way for each valid instance of X, then attribute Y is functionally dependent on attribute X for any relation R.
How do you identify functional dependency?
When two different values of B are related to the same A, this is known as a "functional dependency" A->B.
A key must be distinct, therefore even if two tuples contain the same value for one or more attributes, the key values must differ.
When you take a multiple-choice test, you are relying on <u>recognition</u> , a means of retrieving information out of your long-term memory storage system that helps you choose the correct answer.
