Correct answers - "$(aws ecr get-login --no-include-email) & docker pull 1234567890.dkr.ecr.eu-west-1.amazonaws.com/demo:latest" : The get-login command retrieves a token that is valid for a specified registry for 12 hours, and then it prints a docker login command with that authorization token. You can execute the printed command to log in to your registry with Docker, or just run it automatically using the $() command wrapper. After you have logged in to an Amazon ECR registry with this command, you can use the Docker CLI to push and pull images from that registry until the token expires. The docker pull command is used to pull an image from the ECR registry.
"docker login -u $AWS_ACCESS_KEY_ID -p $AWS_SECRET_ACCESS_KEY" - You cannot login to AWS ECR this way. AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY are only used by the CLI, not docker
"aws docker push 1234567890.dkr.ecr.eu-west-1.amazonaws.com/demo:latest" - docker push here is the wrong answer, you need to use docker pull
"docker build -t 1234567890.dkr.ecr.eu-west-1.amazonaws.com/demo:latest" - This is a docker command that is used to build Docker images from a Dockerfile and a 'context"