The SAP Integration Suite, managed gateway for spend management and SAP Business Network supports the transmission of attachments from an SAP ERP or SAP S/4HANA system. The two standard, supported mechanisms are Generic Object Services (GOS) and the Document Management System (DMS). Specifically, GOS is used to handle attachments at the document header level. For more structured document management, DMS is supported, and it allows for attachments to be linked at both the header and, crucially, the individual line-item level for documents such as purchase orders.

A. SAP SmartForms is a technology for designing and generating formatted output like PDFs for printing or emailing; it is not a system for managing or integrating attachments with transactional data.

C. SAP Change Documents are used to create a log or audit trail of changes made to SAP business objects. They do not have the functionality to store or transmit file attachments.

1. SAP Help Portal: Configuration guide for buying and invoicing with SAP ERP or SAP S/4HANA. In the section "How to enable attachments for documents," the guide explicitly states the supported methods. It details: "SAP Integration Suite, managed gateway for spend management and SAP Business Network supports attachments from Generic Object Services (GOS) and Document Management System (DMS)." It further clarifies for purchase orders: "...you can send attachments from GOS at the header level and from DMS at both the header and the line-item level." This directly supports answers B and D. (Note: Specific document version may vary, but this information is standard across recent versions).

2. SAP Help Portal: SAP Ariba Cloud Integration Gateway overview guide. The section on "Features of SAP Ariba Cloud Integration Gateway" often outlines key capabilities, including attachment handling. It confirms that both GOS and DMS are the standard SAP frameworks leveraged by the integration gateway to send attachments to SAP Business Network. This corroborates that GOS is used for header-level and DMS can be used for line-level attachments.