Messages That Provide a Preliminary Announcement That the Message Is

Messages that provide a preliminary announcement that the message is intended to change our opinion are ________.

A) as effective as those that do not forewarn us of this attempt
B) less effective than those that do not forewarn us of this attempt
C) more effective if the content is humorous,less effective otherwise
D) more effective than those that do not forewarn us of this attempt
E) less effective if the content is humorous,more effective otherwise