The book of Philemon addresses a specific situation involving a slave named Onesimus. What is the theological significance of Paul's request to Philemon regarding Onesimus?

A Paul is asking Philemon to free Onesimus and send him back to assist Paul in his ministry, highlighting the equality of believers in Christ. B Paul is demanding Philemon punish Onesimus severely as an example to other slaves, reinforcing the social hierarchy of the time. C Paul is suggesting Philemon sell Onesimus to another Christian master who can better provide for him. D Paul is encouraging Philemon to simply forgive Onesimus for his past actions without altering his status as a slave.