Refer to the input text as context and select the correct relationship between 'Trulia' and 'Zillow' from the available options.
Options: chief executive officer, chairperson, platform, parent organization

Although Zillow and competitor Trulia ( TRLA ) have a 90% to 95% access to real estate listings, Realtor.com has upwards of 98% coverage with superior timeliness.
parent organization