What does a line hierarchy in repetitive manufacturing represent?

In SAP S/4HANA repetitive manufacturing, aline hierarchy(transaction LDM1) organizes production lines for planning and execution:

A production line with more than one work center(A): A line hierarchy represents a complex production line comprising multiple work centers (defined in CR01/CR02) linked in a hierarchical structure. For example, a main line (top node) might include sub-lines or work centers (e.g., assembly, testing), allowing detailed capacity planning and quantity assignment in MF50 or PP/DS.

Alternative sequence in the routing(B) (CA21, Alternative Sequence) defines optional operation paths, not a line hierarchy.Parallel sequence in the routing(C) (Parallel Sequence) splits operations concurrently, unrelated to line hierarchy structure.Prioritized alternative work centers(D) is managed via production versions or PP/DS mode selection, not line hierarchies, which focus on physical line organization. This is per SAP’s REM line hierarchy definition.