How should an administrator enable Calm?

What role must a user have in order to create or update a Playbook?

A company wants to ensure that all developers are able to request new development environments on demand by using ServiceNow.
The administrator notices that even though developers create new environments, they rarely remove these environments when moving on to new assignments. Today, the administrator has gone into Prism Central to check when the VM was created, in order to reach out to the developer and ask if it can be deleted. The administrator has accidentally deleted the wrong VM in the past.
Which two methods can the administrator use to automate this task to avoid deleting the incorrect VMs? (Choose two.)

Refer to the exhibit.

A subset of Linux VMs are required to be gracefully shutdown each evening. A Playbook is created to shutdown the targeted VMs, however the error message shown in the exhibit is displayed when the Playbook is executed.
What is causing the error message?

An administrator at a busy software development company is looking to roll out Calm for automation and estimates they will be creating 200 Projects, 500 Runbooks, 1500 Blueprints and automating the deployment of 7500 VMs for their development teams.
What size of Prism Central VM(s) is recommended to host the Calm environment?