Consider the following functional dependencies in a database.
$$\eqalign{ & \,\,\,\,Date\,\,of\,\,Birth\,\, \to \,\,Age \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,Age\,\, \to \,\,Eligibility \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,Name\,\, \to \,\,Roll\_number \cr & \,\,\,\,\,Roll\_number\,\, \to \,\,Name \cr & Course\_number\, \to \,\,Course\_name \cr & Course\_number\, \to Instructor \cr & (Roll\_Number,\,Course\_number)\,\, \to \,\,Grade \cr} $$

The relation (Roll_number, Name, Date_of_Birth, Age) is

From the following instance of a relation schema $$R(A, B, C),$$ we can conclude that:

Relation $$R$$ is decomposed using a set of functional dependencies, $$F,$$ and relation $$S$$ is decomposed using another set of functional dependencies, $$G.$$ One decomposition is definitely $$BCNF,$$ the other is definitely. $$3NF,$$ but it is not known which is which. To make a guaranteed identification, which one of the following tests should be used on the decompositions? (Assume that the closures of $$F$$ and $$G$$ are available).

$$R(A,B,C,D)$$ is a relation. Which of the following does not have a lossless-join, dependency preserving $$BCNF$$ decomposition?