What is the purpose of the `args` directive in a `docker-compose.yml` file?

Question

Examine the `docker-compose.yml` file below:
```yaml
services:
  app:
    build:
      context: .
      args:
        ENV: development
```

What is the purpose of the `args` directive in this file?

Accepted Answer

It passes a build argument to the `Dockerfile`.

Answer

It specifies the location of source files.

Answer

It activates the development mode for the container.

Answer

It defines an environment variable for the container.

Question from the Docker compose test