Which of the following is NOT a key piece of master data in the purchasing module of SAP S/4HANA?

In the context of the purchasing module within SAP S/4HANA, the primary focus is on managing the relationships and transactions with suppliers and materials essential for procurement activities. The Supplier Master and Vendor Master are key components, as they contain vital information about the suppliers from whom the organization procures goods and services. The Material Master also plays a crucial role, as it provides detailed information about the materials that are being purchased.

The Customer Master, however, is not relevant in the purchasing module, as it pertains to sales and distribution processes. This master data maintains information about customers that are involved in sales transactions rather than procurement activities. Therefore, it does not contribute to the core functionalities associated with purchasing and is not needed for the operations within the purchasing module.