Final answer:
To set an unencrypted password 'password123' on a Cisco device, the correct command is D) enable password 0 password123, with the '0' specifying that the password should remain clear text.
Step-by-step explanation:
The command would you use to enter the following information: Secret: password123 with no encryption on a Cisco device is D) enable password 0 password123.
The '0' following the 'enable password' indicates that the password should be stored in clear text, which means unencrypted. Option B 'enable password password123' is also used to set an unencrypted password, but option D explicitly specifies by using '0' that the password should not be encrypted, making it the most precise answer according to the question. In contrast, the 'enable secret' commands (options A and C) are used for setting encrypted passwords, which does not meet the 'NO encryption' requirement of the question.