Which of the following is an unacceptable unsubscribe mechanism? A hyperlink included in an email that allows the user to unsubscribe by clicking it A CEM sent via SMS stating that a user can unsubscribe by texting the word "unsubscribe" Any mechanism that requires the user to log-in to carry out the unsubscribe request. A hyperlink included in an email that links the user to a webpage preference centre where they can unsubscribe from receiving all or some types of CEMs from the sender. A CEM sent via SMS stating that a user can unsubscribe by texting the word "STOP