Is There a Best Style for Effective Direction, Planning, and Control

Is there a best style for effective direction, planning, and control of a police agency?

A) Managers who balance both concern for people and concerns for production are the most effective managers.
B) Likert found that managers who focused more attention on people were more successful than job-centered managers.
C) A single style of leadership may not apply to all situations.
D) all of the above