As a new manager, you got to know that the previous manager had a totally different management style, to which the team was used to, what will you do?

We must try to implement  self style smoothly, and let the team know the reason of change of style.

The fact that the team is used to the prior manager's style is not the critical question.  Whether the prior manager's style was effective should be the important consideration.  The prior manager's style may not be effective for the new manager or the team under the new manager's direction.  Strategically thinking, whether one chooses A, B or C depends on the goals of the team, the project and the organization.  

But the best answer is typically B.  Most effective managers have developed their leadership style over time, and that  style is likely part of the reason for his or her selection to the new position.  The chief concepts of the new manager's style should be immediately communicated to the team, with the expectation that team members conform to the new style.  But a good manager should always be open to suggestion and should solicit ideas from the team regarding style, even if it means changing his or her own style as a result.

B.  

but the fact is that this transition of changed management style attitude for your new team will not be smooth. Wherever you go you carry your previous reputation with you and you are treated in the new environment with respect to your prior image of management by both your subordinates and your superiors, in that new working environment. It is not only upto you that you will mold your team into your own matrix but its their response that will define whether you have to keep your own management style or adopt to the style of your predecessor. It's all about control in the end. So if you feel you need to carry on with your own management style to control your new team, go ahead, but  if needs modification due to the attitude of your new team, being a manager you must be flexible enough to adopt to the new environment , so change your style. 

One thing that every manager must keep in mind is that no management practice is the best until it gives you control of your subordinates. because here we are talking in a manager's perspective (which demands control), not a leader's perspective (which gives freedom). 

"ADAPT" and when I say adapt I mean take the best of procedures from both the style.

If your style of management has some good outcomes be firm and  explain the team how it will help in a certain task.

If the previous management style was better than the one you have in your mind, appreciate and adapt.

Unless it is a EGO issue ;) which sadly has no place in professional life.

Certainly implement my style of management smoothly and slowly..

I have to implement my style smoothly step by step and should not be imposed from the day first

Adapt and then change smoothly

He should try to Blend both management styles (previous & his own) with harmony..it might not always be smooth...After all a good Team Lead is one who get things done more efficiently....I would say.... you should lead by example.

Then Company Rules

To answer this we must look at the first and foremost  that which style brings the most benefit to the project. The key to success here is adaptability. In either answer B or C, the team or you adapt to the new management style.

Does the style of the earlier project manager benefit the project, Can it be improved more if change to my style of management. Can there be a marriage of the two styles. are some of the questions you would need to get answers to before coming to a conclusion. Also the responses that you get from the team must be evaluated well before you make the decision.

The best people that can provide you an insight into the previous manager are the employees that reported to that person.  Have a team lunch or meet with the team members individually if it is possible to try to gauge what they liked or disliked about the previous manager. If there is one bad quality in the previous manager, that will be consistent in the feedback of all of the employees.  You can take an example such as "he is always promising the deadlines without consulting the team members as to how long does it take to get things done with at least a95% success rate."