Phase-based maintenance processing is a new concept that was introduced in SAP S/4HANA Cloud 2011 and SAP S/4HANA 2021. It allows you to track the life cycle of the maintenance processes using predefined phases and sub-phases, instead of system and user statuses. Phase-based maintenance processing is activated in the SAP system through the following ways:
* Through Best Practices scope items 4HH and 4HI. These are the new scope items for reactive and proactive maintenance that use the phase model for maintenance requests and orders. You can activate these scope items using the SAP Activate methodology and the SAP Best Practices Explorer12.
* By manually activating the corresponding Business Feature in case Best Practices are not used. If you do not use the Best Practices scope items, you can still activate the phase model for maintenance requests and orders by using the Business Feature switch in the Customizing activity Define Settings for Maintenance Processing34.
Phase-based maintenance processing is not always active in all S/4HANA 2021 editions and above, as it depends on the scope items or the Business Feature switch. Therefore, answer B is incorrect. Phase-based maintenance processing is not activated by installing the corresponding enhancement pack and activating the related business function, as this is the old way of activating new features in SAP ERP. Therefore, answer C is also incorrect. References: SAP S/4HANA Cloud release of 2011 - Asset Management (Maintenance
... and Highlights for Asset Management in SAP S/4HANA 2021 | SAP Blogs