Which menu option is used to change user permissions for Mimecast applications?

The correct choice for changing user permissions in Mimecast applications is the Application Management menu option. This option typically provides administrators with the tools and functionalities needed to oversee various applications within the Mimecast suite, including permissions settings.

In Application Management, administrators can assign or revoke access to specific applications based on the roles and responsibilities of different users within the organization. This ensures that only authorized personnel have access to sensitive information and applications, thus maintaining security and compliance within the organization.

While the other options might include various settings or user configurations, Application Management is specifically tailored to directly facilitate the alteration of permissions, making it the most appropriate choice for managing user access to Mimecast applications.