An Organization Has Setup Auto Scaling with ELB

Multiple Choice

An organization has setup Auto Scaling with ELB. Due to some manual error, one of the instances got rebooted. Thus, it failed the Auto Scaling health check. Auto Scaling has marked it for replacement. How can the system admin ensure that the instance does not get terminated?

A) Update the Auto Scaling group to ignore the instance reboot event
B) It is not possible to change the status once it is marked for replacement
C) Manually add that instance to the Auto Scaling group after reboot to avoid replacement
D) Change the health of the instance to healthy using the Auto Scaling commands