Final answer:
The attorney must keep the property separate until the dispute is resolved, honoring both legal and ethical standards regarding possession of disputed property. This is in line with principles of justice and avoids conflicts of interest.
Step-by-step explanation:
When an attorney is in possession of property wherein multiple parties claim interests, the ethical and legal approach is for the property to be kept separate until the dispute is resolved. This option aligns with the principles of justice in acquisition and justice in transfer. These principles essentially hold that a person is entitled to a holding if it is acquired justly either through initial ownership or through a proper transfer. It also reflects the broader legal standards regarding the management of property at dispute and avoiding conflicts of interest, as established in cases like Glasser v. United States, where a defense lawyer's conflict of interest due to simultaneous representation of codefendants was found to violate the Assistance of Counsel Clause of the Sixth Amendment.
In adhering to these principles and legal precedents, it is clear that the correct answer to the original question is A) Be kept separate until the dispute is resolved. This is because attorneys are bound by professional responsibility to preserve the integrity of disputed property and to prevent any appearance of impropriety or self-interested behavior that could compromise the interests of the claimants or the justice process.