What activities are applied to the entire system and cannot be changed after confirmation in...

Comprehensive and Detailed 150 to 250 words of Explanation From SAP S/4HANA Cloud Public Edition, Management Accounting documents:

In SAP Central Business Configuration (CBC), certain "foundational" settings are locked once they are confirmed during the initial organizational structure setup. These settings are system-wide and irreversible because they form the basis for all subsequent transactional data.

The Group currency (Option A) is one such setting. Once the group currency is defined for the entire landscape, it cannot be changed, as this would invalidate historical data and consolidated reporting94. Similarly, the Fiscal year variant (Option D) is fixed after confirmation This variant defines the number of periods in a year and the start/end dates for those periods; changing this after the system is in use would lead to severe data inconsistency in the Universal Journal96. While scoping (Option B) and specific product configurations (Option C) can often be adjusted or refined throughout the implementation, these two core accounting dimensions are permanent choices