In the book of Philemon, what social and legal context surrounding slavery influenced Paul's appeal on behalf of Onesimus?

A Roman law strictly forbade manumission (freeing) of slaves under any circumstances. B Slaves were considered property with virtually no legal rights, and runaway slaves faced severe punishments, including death. C Christian converts were automatically granted freedom from slavery upon baptism. D Roman society largely viewed slavery as morally reprehensible and actively sought its abolition.