What Was Griffin's "Cause for Pause" Regarding Credibility

What was Griffin's "cause for pause" regarding credibility?

A) Communication theory should deal with the "how" and not the "who."
B) Credibility is transitory and subject to interpretation.
C) It doesn't really address the process of communication, only the evaluation of its source.
D) By focusing on the source of a message, we may lose sight of the intrinsic value of what's being said.