Which two playbook functionalities allow looping through a group of tasks during playbook execution?

The correct choice is Sub-playbooks. Sub-playbooks are specifically designed to allow the execution of a set of tasks that can be reused and looped through within a main playbook. This functionality is crucial for streamlining processes where the same sequence of tasks needs to be executed multiple times, either for different inputs or under different conditions, without having to duplicate the task definitions in the main playbook.

Using Sub-playbooks, you can effectively manage complex workflows by isolating specific operations into smaller, manageable units. This not only keeps the main playbook organized but also enhances maintainability and clarity, allowing for easier updates and troubleshooting when necessary.

In contrast, while playbook functions and common polling playbooks may play essential roles in the overall execution and orchestration of tasks, they do not specifically facilitate the looping mechanism. Similarly, playbook tasks are individual actions within a playbook but do not inherently allow looping through multiple tasks autonomously. The combination of using sub-playbooks for such looping tasks is what enhances the flexibility and capability of playbook execution.