Scrypt is safer than MD5, so answer A is wrong and answer D is correct R1(config)#username user secret ?0 Specifies an UNENCRYPTED secret will follow5 Specifies a MD5 HASHED secret will follow8 Specifies a PBKDF2 HASHED secret will follow9 Specifies a SCRYPT HASHED secret will follow<0-9> Encryption types not explicitly specifiedLINE The UNENCRYPTED (cleartext) user secretLINE The UNENCRYPTED (cleartext) user secret Reference: https://community.cisco.com/t5/networking-documents/understanding-the-differences-between-the-c