What happens if the possessor refuses to specify which slave belongs to Zaid?

Primary text

If the possessor refuses to specify, and the claimant (Zaid) specifies the slave, saying, "This is my slave," the possessor is then required to answer the claim. If the possessor denies ownership and takes an oath, the situation is treated as if the possessor had specified the other slave. If the possessor refuses the oath (nakul), judgment is passed against them. If the possessor admits ownership to Zaid, it is treated as if they had specified the slave initially.