Department head Matt wants the department members to be convinced of the merits of a new procedure. He gets a well-liked worker to speak in favor of the new procedure. Matt is using the persuasion principle known as:

A) reciprocity.
B) consistency.
C) scarcity.
D) social proof.

Matt is using the principle of social proof, which relies on people's tendency to look to others, especially those they like or respect, for cues on how to think, feel, and act. By having a well-liked worker speak in favor of the new procedure, Matt is leveraging this worker's influence to persuade others in the department.