Under What Circumstances Might Divorce Be the Preferred Option

Under what circumstances might divorce be the preferred option?

A) Two parents who have irreconcilable differences living together but who can respectfully disagree and work together once the marriage dissolves
B) Two parents who have reconcilable differences but won't work to come to agreement on anything
C) Two parents who have irreconcilable differences whether they are married or not, and the fighting continues under both conditions
D) Two parents who love each other but want to live in different towns