How to find highest normal form of a relation, given its functional dependencies
In your example $C$ is derived attribute from $A, B$, but none of: $D, E, F, G$ is more dependent on $C$ than $A, B$, or solely functionaly dependent on $C$, so there is no transitive dependency. Since you have 2NF it is in 3NF.

For BCNF it is sufficient to be in 3NF and do not have overlapping candidate keys, which you do not have, hence it is in BCNF.