Explanation

The "enable secret" password is always encrypted (independent of the "service passwordencryption" command) using MD5 hash algorithm. The "enable password" does not encrypt the password and can be view in clear text in the running-config. In order to encrypt the "enable password", use the "service password-encryption" command. This command will encrypt the passwords by using the Vigenere encryption algorithm. Unfortunately, the Vigenere encryption method is cryptographically weak and trivial to reverse.
The MD5 hash is a stronger algorithm than Vigenere so answer 'The enable secret password is protected via stronger cryptography mechanisms' is correct.