_____ power is considered an informal power base.

A) Legitimate
B) Coercive
C) Expert
D) Reward

Expert power is considered an informal power base because it is based on an individual's knowledge, skills, and expertise in a certain area, rather than on any formal position or authority. Legitimate power is a formal power base that comes from an individual's position within an organization, coercive power is based on the ability to punish or control others, and reward power is based on the ability to provide benefits or incentives.