The correct answer is 'Setting up a Jenkins pipeline.' Jenkins is a popular automation server that is widely used for implementing continuous integration and continuous deployment pipelines. By setting up a Jenkins pipeline, developers can automate the process of building, testing, and deploying their code whenever a commit is made. While 'Configuring a Git hook' can trigger actions upon code changes, it lacks the robust pipeline features Jenkins offers. 'Using cron jobs for scheduled deployments' is not the best solution as it doesn't provide immediate deployments following code commits. 'Automating with shell scripts' can be part of a CI/CD pipeline but on its own is not sufficient for establishing a full pipeline that encompasses building, testing, and deploying.