Question from the Docker compose test

services:
  web:
    image: "nginx:latest"
    env:
      - MY_VAR=value

services:
  web:
    image: "nginx:latest"
    variables:
      MY_VAR: value

services:
  web:
    image: "nginx:latest"
    environment:
      MY_VAR: value

services:
  web:
    image: "nginx:latest"
    set:
      - MY_VAR=value