How is خُسْرٍ treated when pausing?

Al-ʿAṣr and At-Takāthur: Applied Ghunnah, Madd, Lām and Waqf

• No tanwīn nūn; rāʾ becomes sākin
• Full tanwīn must remain
• A mīm is inserted
• A new fatḥah is added to rāʾ