Question: To set up Hadoop workflow with synchronization of data between jobs that process tasks both on disk and in memory, use the `___` service, which is `___`.

  1. Oozie; open source
  2. Oozie; commercial software
  3. Zookeeper; commercial software
  4. Zookeeper; open source

Answer: The correct answer of the above question is Option D:Zookeeper; open source