Final answer:
In a DRP system, the planned order quantity follows the order rule attached to the item, which can be based on various inventory management strategies and constraints.
Step-by-step explanation:
In a Distribution Requirements Planning (DRP) system, the generated planned order quantity should follow option (d) the order rule attached to the item. This means that the quantity may not always be equal to the net requirements or the negative projected available balance; nor does it necessarily align with the economic order quantity (EOQ) unless the EOQ is the defined order rule for that item. Essentially, the planned order quantity will vary depending on factors such as EOQ, minimum order quantity, package size, or other constraints that are defined within the inventory management strategy of the organization.