Which command prevents unencrypted passwords from displaying in plain text in a configuration file?

• A. (config)# enable password secret
• B. (config)# enable secret Secret_Password
• C. (config-line)# password secret
• D. (config)# service password-encryption

Answer: (D)

Main idea: hiding passwords in the config by turning passwords into encrypted form so they don’t appear as plain text when the configuration is viewed or saved.

The command enables password encryption globally, so any password lines in the configuration (enable, console, VTY, etc.) are stored in an encrypted form in the startup and running configs. This means someone looking at the config won’t see the actual passwords in clear text. While using enable secret also prevents plain-text display by hashing the value, this particular command is the standard way to ensure all password entries in the config are encrypted.