Despite serving as a punching bag for media executives frustrated by mobile video, Nielsen is unlikely to be knocked from its perch as the industry standard for buying and selling advertising even as leading rivals  Rentrak ( RENT - Get Report ) and comScore ( SCOR - Get Report )  plan to merge.
Refer to the input text as context and select the correct relationship between 'comScore' and 'Rentrak' from the available options.
Options: location of formation, founded by, platform, owner of