Take context from the input text and decide on the accurate relationship between 'comScore' and 'Rentrak' from the options provided.
Options: platform, owner of, brand, employer

Investors and security holders will be able to obtain free copies of the registration statement and the joint proxy statement/prospectus (when they are available) and any other documents filed by comScore and Rentrak with the SEC at the SEC's website at www.sec.gov .
owner of