Comprehensive and Detailed Explanation From SAP S/4HANA Cloud Public Edition, Management Accounting documents:

In a make-to-order (MTO) business scenario, the integration between the sales process and management accounting is critical for tracking order-specific profitability5.

The true account assignment in a sales order item for this scenario is the Profitability Segment. By assigning the item directly to a profitability segment, all associated costs (such as COGS) and revenues from the sales process flow directly into Margin Analysis. This enables real-time reporting on the profitability of individual orders or customers61. While a profit center (Option C) is also derived, it serves as a reporting dimension rather than a true CO account assignment object that can collect costs and revenues in the same way as a profitability segment.