________ might be called vocal authority because it involves actively applying legitimate and coercive power to influence others.

A) Ingratiation
B) Upward appeal
C) Persuasion
D) Assertiveness
E) Information control

Assertiveness involves the use of legitimate and coercive power to influence others, hence making it the best choice for vocal authority. Ingratiation and upward appeal involve using more subtle approaches to influence others, while persuasion and information control do not necessarily involve the use of power to influence others.