An application is hosted on Google Kubernetes Engine. A new JavaScript module is created to work with the existing application. Which task is mandatory to make the code ready to deploy?

While creating a Dockerfile is a common method for containerization, option C describes the fundamental mandatory task of containerization itself, making it more general and accurate than just mentioning one specific tool.

Rewriting the code in Python is not mandatory, as Kubernetes can host applications developed in any language, including JavaScript, as long as they are containerized.

Kubernetes Engine deploys and manages applications within containers, so any new application component, such as a JavaScript module, must be containerized to run on the platform. This involves packaging the code and its dependencies into a container image, which serves as a 'wrapper' for deployment.

Rebase from an upstream git repo is a version control operation and is not a mandatory step for making the code technically ready for deployment on Kubernetes.