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

Which methods canyou 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