It is impossible for a person who does not have a certificate of first-class in Mandarin to become a moderator because the moderator cannot pronounce substandardly. Which of the following premise is needed for the above argument? ['People who do not have a first-class certificate will have poor pronunciation.', 'Moderators who do not pronounce well may not have first-class certificates.', 'A person with a bad pronunciation may get a first-class certificate.', 'A non-pronounced moderator cannot be a popular moderator.']