Refer to the input text as context and select the correct relationship between 'Facebook' and 'Mark Zuckerberg' from the available options.
Options: subsidiary, founded by, location of formation, chairperson

Facebook (NasdaqGS: FB - news ) is working on a 'dislike' button, its founder Mark Zuckerberg has announced, after years of resisting popular demand for such a tool.
founded by