Final answer:
As a Teams Administrator, John should use the New-MsolGroup cmdlet in PowerShell to create Microsoft 365 groups. This cmdlet is appropriate for managing group-related tasks in a Microsoft 365 environment.
Step-by-step explanation:
To create Microsoft 365 groups as a Teams Administrator using PowerShell, John should use the New-MsolGroup cmdlet. This cmdlet is part of the Azure Active Directory PowerShell module, which is used for managing Microsoft 365 services. The cmdlet allows administrators to create new groups that can be used within Microsoft Teams and other Microsoft 365 services. The New-MsolUser cmdlet is for creating new users, the New-Team cmdlet is specifically for creating teams within Microsoft Teams, and New-MsolRoleAssignment is for assigning roles to users. Therefore, John should utilize the New-MsolGroup cmdlet for his task of creating groups.