Answer and Explanation:
I'd say a democratic leader is the most effective leader but a transformational leader could be effective.
A democratic leadership style is a leadership style in which members of the group take a more participative role in the decision-making process. They usually report higher levels of job satisfaction and companies can benefit from individualistic creativity. They also, almost always ask/give feedback and they also prefer (give) time for meetings in person rather than over the phone/computer.
A transformational leader influences (Work Hard, Inspire, Emphasize a Common Mission, etc) and also inspirational Motivation. They're also communicative and are good at communicating.