Consider the following functional dependencies in a database:

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Consider the following functional dependencies in a database:
Date_of_Birth → Age Age → Eligibility
Name → Roll_number Roll_number → Name
Course_number → Course_name Course_number → Instructor (Roll_number, Course_number) → Grade
The relation (Roll_number, Name, Date_of_birth, Age) is

1. in second normal form but not in third normal form
2. in third normal form but not in BCNF
3. in BCNF
4. none of the above

Correct Option: D

There are three FDs that are valid from the above set of FDs for the given relation :
Date of Birth → Age
Name → Roll number
Roll number → Name
Candidate keys for the above are :
(Date - of - Birth, Name) and
(Date-of - Birth, Roll - number)
clearly there is partial dependency here (Date of Birth → Age) and Age is not a prime attribute. So it is only in 1NF.