Which methods can you use to integrate purchase orders within SAP Ariba Buying and Invoicing? Note: There are 2 correct answers to this question.

Which methods can you use to integrate purchase orders within SAP Ariba Buying and Invoicing? Note: There are 2 correct answers to this question.
A . Direct order method
B . Asynchronous order method
C . ERP order method with or without acknowledgement
D . Indirect order method

Answer: A, C