Which of the following is not a method of hardening devices in a cloud datacenter?

Removing all admin accounts is not a method of hardening devices in a cloud data center because it undermines necessary administrative functions. Admin accounts are essential for managing and maintaining cloud resources efficiently. Instead of eliminating these accounts entirely, the objective is to secure them properly by implementing strong password policies, removing default passwords, and ensuring limited access to physical hardware.

Hardening involves strengthening security measures around existing configurations and controls rather than removing critical access altogether. Proper hardening techniques focus on enforcing strong authentication methods, ensuring least privilege access, and employing stringent security protocols to protect devices and data. Therefore, while removing all admin accounts may seem like a way to tighten security, it would actually lead to operational inefficiencies and potentially greater security risks, as there would be no authorized personnel to manage and secure cloud resources effectively.