What is the purpose of specifying a planning horizon?

A.  Only materials manifesting a planning-relevant change within the planning horizon are taken into account in the MRP run (where NETPL is used).
B.  To specify whether forecasts are included in the material requirement calculation.

C. To specify that only externally procured (and not internally procured) items are included in the net change MRP run.

D. To specify whether a NETCH (net change in complete horizon) or a NETPL (net change in planning horizon) will take place in the next MRP run.