What is the best approach to conflict resolution?

It depends on the situation. All option may be applied. First of all it is essential to make an ESTIMATION of SITUATION by determining the source of possible conflict. The sides offen gives evidences of what they want. After it could be applied options by turn. The last option must be withdrawal.

Option B. There has never been any conflict to the best of my knowledge that was resolved without dialogue and diplomacy. 

The answer is : Option B- Smoothing

Option-C Compromising............................. In other words negotiation

When a dispute arises, often the best course of action is negotiation to resolve the disagreement.

The goals of negotiation are:

• To produce a solution that all parties can agree to
• To work as quickly as possible to find this solution
• To improve, not hurt, the relationship between the groups in conflict

Option (D) Confronting -----------

Thanks for the invite.

It is D - Confronting

Confronting results in identifying the source and root cause of of the conflict.