Scenario: The company is designing a cost-efficient environment for the call center workers. The IT department is replacing the existing thin clients with newer models.

A hosted shared desktop environment (often implemented using technologies like Citrix XenApp or Microsoft RDS) is highly cost-efficient for call center workers because multiple users share a single server's resources. This reduces the number of underlying VMs and OS licenses needed, making it ideal for task-oriented users who primarily run a limited set of applications.

Hosted VDI (Virtual Desktop Infrastructure) provides dedicated virtual machines to each user, which is less cost-efficient than a shared desktop model due to higher resource requirements (storage, CPU, memory) per user.

Streamed VHD (Virtual Hard Disk) typically refers to application or OS streaming solutions, which might be part of an environment but don't define the entire desktop delivery model as cost-efficiently as a shared session host for call centers.

A local VM implies running a virtual machine directly on the end-user device or a powerful local workstation, which contradicts the use of thin clients and the goal of a centralized, cost-efficient environment.