Option (C) . Since it is given that out of F and G, one is 3NF and other is BCNF then clearly we can apply BCNF defintion to differentiate between F and G.
Option (D) is useless as 3NF defintion will be satisfied by both the Functional Dependencies sets.
Option (A) and Option (B) are not the criteria to decide about BCNF and 3NF. They are criteria for Relation decomposition.
Eventhough Decompostion has been used here and some give Option (A) Dependency Preservation as answer but I will go with BCNF defintion as the distinguishing factor.