Which statement is true regarding infrastructure management when specified by the customer?

The choice indicating that the customer loses the ability to create additional instances is correct in a context where infrastructure management is explicitly specified by the customer, often implying a managed service model. In such scenarios, the customer typically has limitations placed upon them to enhance control, manage performance, or streamline operations according to accordance with the service provider's infrastructure management policies.

When a customer specifies how their infrastructure should be managed, they may opt for a managed service solution where the provider handles the underlying infrastructure. This could involve restrictions on the customer’s ability to create new instances to ensure resource management, compliance with policies, and maintenance of performance standards. Essentially, the service provider retains more control to prevent issues such as over-provisioning or conflicts in resource allocation.

In contrast, the other choices suggest scenarios where the customer retains or is obligated to assume responsibilities that are generally not aligned with the premise of managed services, where the focus tends to be on centralized management and operational oversight by the service provider. By clarifying that the customer loses the ability to create additional instances, it emphasizes a key aspect of managed infrastructure management, which is to balance freedom with governance for optimal performance and stability.