Which command configures an MD5-encrypted enable password?

The command that configures an MD5-encrypted enable password is "enable secret password." This command creates an encrypted password for the privileged EXEC mode on a Cisco device. Unlike the "enable password" command, which simply sets a plaintext password, the "enable secret" command uses the MD5 hashing algorithm to encrypt the password. This encryption enhances security because the actual password is not stored as plaintext in the device's configuration, making it significantly harder for an unauthorized user to retrieve it.

This is crucial in network security, as it ensures that sensitive credentials are protected from readily being discovered by individuals who might have access to the device's configuration file. As a result, "enable secret password" is the preferred method for setting enable passwords on Cisco devices due to its added security layer.

The other options do not provide the same level of security: setting a plaintext password or using commands that do not exist in Cisco IOS would not achieve the goal of configuring a secure, encrypted enable password.