Which two conventions of the Heroku platform reflect the Twelve-Factor methodology's recommendation to "execute the app as one or more stateless processes?" (Choose two.)

Which two conventions of the Heroku platform reflect the Twelve-Factor methodology’s recommendation to "execute the app as one or more stateless processes?" (Choose two.)

Which two conventions of the Heroku platform reflect the Twelve-Factor methodology’s recommendation to "execute the app as one or more stateless processes?" (Choose two.)
A . Log messages from each of an app’s dynos are kept separate from each other.
B . Heroku apps define process types in a Procfile.
C . A Heroku app’s config vars are deleted on deploys and app restarts.
D . Dynos have an ephemeral filesystem.

Answer: B, D