Which AWS service should the company use to meet these requirements?

Explanations:

Amazon AppStream 2.0 is primarily used for streaming applications, not providing full desktop environments. It allows users to access applications from their devices but does not deliver a complete desktop experience.

AWS AppSync is a service for building GraphQL APIs and managing application data, not related to virtual desktops or desktop infrastructure. It does not provide any desktop access capabilities.

Amazon FSx for Windows File Server is a managed file storage service that provides file shares but does not offer virtual desktop infrastructure. It is used for file storage rather than delivering desktops to users.

Amazon WorkSpaces is a managed desktop-as-a-service solution that allows users to access virtual desktops from any device. It is designed for secure access to company-provided desktops and meets the requirement for a virtual desktop infrastructure.