An organization is trying to create various IAM users. Which of the below mentioned options is not a valid IAM
username?

A.
John.cloud

B.
john@cloud

C.
John=cloud

D.
john#cloud

Explanation:
AWS Identity and Access Management is a web service which allows organizations to manage users and user
permissions for various AWS services. Whenever the organization is creating an IAM user, there should be a
unique ID for each user. The names of users, groups, roles, instance profiles must be alphanumeric, including
the following common characters: plus (+., equal (=., comma (,., period (.., at (@., and dash (-..