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For a database relation $R(a, b, c, d)$, where the domains $a, b, c, d$ include only atomic values, only the following functional dependencies and those that can be inferred from them hold

• $a \rightarrow c$
• $b \rightarrow d$

This relation is

1. in first normal form but not in second normal form

2. in second normal form but not in first normal form

3. in third normal form

4. none of the above

Ck is ab.

Since all a,b,c,d are atomic so the relation is in 1 NF.

Now check the FD s.

a->c(P->NP)

b->d(P->NP)

Since there are partial dependencies,so it is not 2 NF.

a}Ans 1NF but not 2NF
selected by
by using decomposition in ac bd ab

ab is the candidate key.