A: Secure environment variables
Another method (another than a secret volume) for providing sensitive information to containers (including Windows containers) is through the use of secure environment variables.
E: Use a secret volume to supply sensitive information to the containers in a container group. The secret volume stores your secrets in files within the volume, accessible by the containers in the container group. By storing secrets in a secret volume, you can avoid adding sensitive data like SSH keys or database credentials to your application code.
Reference:
https://docs.microsoft.com/en-us/azure/container-instances/container-instances-volume-secret