$6.$ Consider the following relation R and its set of functional dependencies:

R $=($A$,$ B$,$ C$,$ D$,$ E$)$

FDs $=\{$A$->$ BC$,$ CD$->$ E$,$ B$->$ D$,$ E $->$ A$\}$

a$.$ What are the different candidate keys in this relation?

$[2$ Marks$]$

b$.$ Is this relation in BCNF$?$ If yes how, if not then make it compliant with the BCNF$.$

$[2$ Marks$]$

c$.$ Is this relation in $3$NF$?$ If yes how, if not then make it compliant with the $3$NF$.$

$[1$ Mark$]$