Which of the Following Managers Is Effective

Which of the following managers is effective?

A) Dorothy, who uses coercive power sparingly because it rob employees of their dignity
B) Marcus, who uses reward power sparingly when trying to motivate employees
C) Vanessa, who uses reward power in a controlling manner
D) Felix, who ignores the opinions of other people because he has considerable expert power
E) Annis, who uses coercive power frequently to keep her employees in line