Consider following relation with schema $R(A,B,C,D)$ and functional

dependencies:

$ABC,CD,$ and $DA.$

$BC,$ and $BD.$

$ABC,DC,$ and $BD.$

a$.$ List all candidate keys

b$.$ Check whether the relation is in $3NF$ or not.

c$.$ Decompose the relations, as necessary into collections of relations that

are in $3NF.$

d$.$ Decompose the relations, as necessary into collections of relations that

are in BCNF$.$

Put the following unnormalized relation $($Students$)$ in INF, $2$NF then

$3NF.$