In the book of Philemon, what is the primary appeal Paul makes regarding Onesimus, the runaway slave?

A That Philemon should accept Onesimus as a beloved brother in the Lord. B That Philemon should grant Onesimus his freedom and send him back to Paul for ministry. C That Philemon should sell Onesimus to another Christian master who will treat him well. D That Philemon should publicly denounce Onesimus as an example to other slaves.