What is the relationship between 'Sheryl Sandberg' and 'Facebook' in the context of the input sentence.
Options: distribution format, member of, employer, director/manager

SAN FRANCISCO, July 6 (Reuters) - Facebook Inc's Chief Operating Officer Sheryl Sandberg is taking a seat on the board of SurveyMonkey, the online polling company that was run by her late husband, Dave Goldberg.
employer