Correct Answer: A. Operator

Short Explanation with reference: A command policy is a set of rules that regulates which commands, command groups, virtual servers, and other entities that users and user groups are permitted to use on a Citrix ADC appliance1. Citrix ADC provides a set of built-in command policies that have predefined permission levels for different types of users1. The built-in command policy permission levels are as follows1:

Read-only: Users can view the configuration of the appliance, but cannot modify it. They can also view statistics and run show commands.

Operator: Users can view and modify the configuration of the appliance, but cannot save the configuration or access the shell. They can also enable and disable services and servers, clear counters, and run show commands.

Network: Users can view and modify the network configuration of the appliance, such as interfaces, routes, VLANs, and so on. They can also save the configuration and access the shell.

Sysadmin: Users have full access to all commands and features of the appliance.

To create local, limited-privilege user accounts for other administrators who require only read-only access and the ability to enable and disable services and servers, the administrator can use the built-in command policy permission level of Operator (option A). This permission level allows users to perform these tasks, but not others that are not required or authorized1. The other options are incorrect because they either grant more privileges than necessary or do not allow enabling and disabling services and servers. Therefore, the correct answer is A. Operator.