What is the relationship between Edward Snowden and National Security Agency 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 case was initiated by Austrian activist Max Schrems, who claims that techniques used by the US National Security Agency (NSA) -- as revealed by whistleblower Edward Snowden -- meant that the privacy of his user data could not be guaranteed once it had been transferred across the Atlantic.

Answer: employer