Final answer:
Podman is the best software package that meets the requirements for running an older company-produced application independently on various Linux distributions as it can run rootless, is modular, and offers command-line usage without the need to create images.
Therefore, the correct answer is: option c). podman
Step-by-step explanation:
To address the need for running an older, company-produced application independently on various Linux distributions using container technology with the capability to run rootless and modularly, the most suitable option from the list would be Podman.
Docker is also a popular container management tool, but its architecture is not as modular as required by the question. AppImage and Flatpak are more focused on packaging and distributing desktop applications and don't offer the same containerization capabilities that are required for this scenario.
Podman offers a daemonless, rootless container engine, which provides better security and simplifies the management of containers, especially on personal systems or shared environments. It's also highly modular, allowing for significant flexibility in deployment and use.
As the question highlights that the need to create images is not important and the software only needs to be run from the command line, Podman's compatibility with Docker CLI commands makes it an excellent choice for users familiar with Docker but requiring the additional capabilities that Podman offers.