What is the relationship between comScore and Rentrak in the context of the input sentence. Choose an answer from: product/material produced; manufacturer; distributed by; industry; position held; original broadcaster; owned by; founded by; distribution format; headquarters location; stock exchange; currency; parent organization; chief executive officer; director/manager; owner of; operator; member of; employer; chairperson; platform; subsidiary; legal form; publisher; developer; brand; business division; location of formation; creator.

"The merger between comScore and Rentrak signals an important step forward to address the measurement mandate: a call for investment in common GRP and ROI metrics across all platforms, from time shifted viewing to mobile.

Answer: owner_of