The Kanban control cycle is the core master data element that defines the relationship between a demand source and a supply source. The Production Supply Area (PSA) is the specific location on the shop floor (the demand source) where the material is required and consumed. The Replenishment Strategy is defined within the control cycle to determine how the material is to be replenished (e.g., via in-house production, external procurement, or stock transfer), thereby defining the link to the supply source and the replenishment process itself.

A. Routing: A routing specifies the sequence of operations for in-house production; it is a detail of a specific replenishment strategy, not the element that defines the core supply-demand relationship.

B. Work Center: A work center is a location where production operations are performed. While a PSA is often assigned to a work center, it is the PSA itself that acts as the demand source in the Kanban process.

1. SAP S/4HANA Product Documentation: Kanban > Master Data for Kanban > Control Cycle. The documentation states, "You create a control cycle for a material that is to be replenished using Kanban for a specific production supply area (PSA)... In the control cycle, you define the Kanban process, for example, by specifying the replenishment strategy." This confirms that the PSA (demand source) and replenishment strategy (link to supply source) are fundamental.

2. SAP S/4HANA Product Documentation: Production Supply Area (PSA). This section details that the PSA is the "stocking location near the production line from which the material is taken directly for production." This establishes it as the demand source.

3. SAP Training Courseware TS422 (Production Planning in SAP S/4HANA): Unit: Lean Manufacturing, Lesson: Kanban. The course material explicitly details the creation of a control cycle (transaction PKMC), highlighting the mandatory entry of the Production Supply Area and the selection of a Replenishment Strategy as the primary parameters for defining a Kanban loop.