Docker is aOnly container runtime toolOnly container building toolFull feature container management toolNone of the above

Breakdown the Problem

We need to identify the correct description of Docker from the given options.

Relevant Concepts

Docker is generally understood as a tool used for containerization, which includes elements for building, managing, and running containers. Therefore, we must evaluate each description against this understanding.

Analysis and Detail

1. Only container runtime tool: This is inaccurate because Docker does more than just run containers.
2. Only container building tool: This is also incorrect; while it has building functionalities, it handles more than just that.
3. Full feature container management tool: This is the most accurate description, as Docker encompasses creating, deploying, and managing containers.
4. None of the above: Since one option is correct, this choice is incorrect.

Verify and Summarize

The most comprehensive definition of Docker reflects its broad capabilities beyond just building or running, making it a full-featured container management tool.

Final Answer

The correct description of Docker is: Full feature container management tool.