To limit the choice of order reasons for a sales document, you should:
C . Assign the permitted order reasons to the relevant sales document type.
This approach allows you to control which order reasons are available for selection when creating sales documents of a particular type, ensuring consistency and adherence to business rules specific to different sales processes or scenarios. By configuring the allowed order reasons at the sales document type level, you can tailor the order processing workflow to meet specific business requirements and constraints.