You need to create an autoscaling managed instance group for an HTTPS web application. You want to make sure that unhealthy VMs are recreated. What should you do? 

Answer options:

A. Create a health check on port 443 and use that when creating the Managed Instance Group.
B. Select Multi-Zone instead of Single-Zone when creating the Managed Instance Group.
C. In the Instance Template, add the label ˜health-check`.
D. In the Instance Template, add a startup script that sends a heartbeat to the metadata server.

C

Reference: https://cloud.google.com/compute/docs/instance-groups/creating-groups-of-managed-instances