Which of the Following Is NOT an Accurate Assertion About

Which of the following is NOT an accurate assertion about word-of-mouth?

A) Word-of-mouth is a marketing tool.
B) Using word-of-mouth is more challenging than other promotional efforts.
C) Word-of-mouth relies on explicit channels to the consumer.
D) There is no formal mechanism for marketers to identify word-of-mouth channels.
E) Word-of-mouth is powerful because it has a high measure of credibility with consumers.