Final answer:
The Shared Services HR model is the structural alternative described in the question, where centers with specific areas of expertise develop HR policies and units can select services as needed.
Step-by-step explanation:
The structural alternative described in the question is the Shared Services HR model. In this model, centers with specific areas of expertise develop HR policies in those areas, and each unit can select what it needs from a menu of these services.
For example, a large organization may have a center for recruitment and another center for employee benefits. Each unit within the organization can choose to access the recruitment services from the recruitment center and the employee benefits services from the benefits center.
This model allows for specialization and expertise while also providing flexibility for different units to tailor their HR services to their specific needs.