What is the first step in creating a forest root trust from CorpNet.local to PartnerCorp.xyz?

The correct answer is to access Server Manager and select Tools > Active Directory Domains and Trusts because this is the starting point for managing trusts within an Active Directory environment. The Active Directory Domains and Trusts tool provides administrators with the necessary functionality to create and manage trusts between different Active Directory domains.

When setting up a forest root trust, it's vital to use this management tool to ensure that the trust relationship between CorpNet.local and PartnerCorp.xyz is properly defined and configured. The Server Manager allows you to navigate through Active Directory structures and initiate trust creation, making it the first step in the process.

The other options, while they involve interactions with the domains or require specific actions related to trust creation, do not represent the initial step needed to begin the trust creation process. They are more specific actions that would come later once you have accessed the necessary management tool.