Which three of these listed elements are required for this scenario?

IT Services would like to automate the allocation of software applications. The company uses a modern virtual desktop platform with software management capabilities, and the platform supports interoperability via a REST API.

The following requirements have been established for this project:

 Business users will use a self-service portal to request software added to their existing system.

 The requestor may select one or more software applications from a list during the request.

 The software application list must be up-to-date.

 The virtual desktop team will provide REST API calls needed to interface with the existing platform.

Which three of these listed elements are required for this scenario? (Choose three.)
A . Customization of XaaS form
B . vRealize Orchestrator workflow with script action
C . Resource mapping
D . Resource action
E . External value definition