In complaints processing in a standard SAP S/4HANA system, which documents can only be created with reference to a billing document? Choose Two correct answers.

In complaints processing in a standard SAP S/4HANA system, which documents can only be created with reference to a billing document? Choose Two correct answers.
A . Invoice correction request
B . Credit memo request
C . Invoice cancellation
D . Subsequent delivery free of charge

Answer: A,C