Which types of field selection keys are available for purchasing documents in SAP Materials Management?

In SAP Materials Management, the field selection keys for purchasing documents are used to control the visibility and editability of fields based on certain criteria. Item category is a correct choice because it directly influences the nature of the purchasing document, determining how the system handles material movement, pricing, and other essential attributes within the procurement process.

Different item categories define how items are processed in the purchasing cycle, such as standard procurement, subcontracting, or external services. Each category may have specific fields required or allowed, affecting how purchasing information is captured and leveraged in the system. This functionality is integral for ensuring that the necessary data is provided for different types of procurement processes and helps in maintaining data integrity and effectiveness in purchasing operations.

The other options mentioned do not represent types of field selection keys specifically associated with defining the behavior of purchasing document fields in the way that item category does. For instance, purchasing organization, workflow status, and transaction types pertain to broader configuration aspects rather than the specific control of field properties.