Which additional instruction must be added to the command 'ipconfig' to display the contents of the DNS cache?

The command 'ipconfig' is a command line utility in Windows that is used for network configuration. To specifically display the contents of the DNS cache, the additional instruction that must be added to the command is "/displaydns."

When this instruction is used in conjunction with 'ipconfig,' it triggers the system to retrieve and show the data stored in the DNS resolver cache. This cache contains records of all the recent domain name resolution processes performed by the DNS client, which is helpful for troubleshooting connectivity issues or understanding how domain names are being resolved by the system.

The other options do not correspond to valid instructions recognized by the 'ipconfig' command. Each of those alternatives does not fulfill the function of displaying the contents of the DNS cache in a Windows environment. Thus, using "/displaydns" is the only correct way to achieve the intended outcome.