Which one of the following statements about normal forms is FALSE?

Relation $$R$$ with an associated set of functional dependencies, $$F,$$ is decomposed into $$BCNF.$$ The redundancy (arising out of functional dependencies) in the resulting set of relations is

Consider a schema $$R(A,B,C,D)$$ and functional dependencies $$A \to B\,\,$$ and $$C \to D\,\,$$. Then the decomposition of $$R$$ into $${R_1}\left( {AB} \right)$$ and $${R_2}\left( {CD} \right)$$ is

Let $$R=(A,B,C,D,E,F)$$ be a relation scheme with the following dependencies: $$C \to F,\,E \to A,\,EC \to D,\,A \to B.$$ Which of the following is a key for $$R?$$