What is the relationship between Office 365 and Microsoft 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 rapidly changing threat landscape and the accelerating transition to the cloud and the migration to Microsoft Office 365 in particular continue to be the key secular trends that are helping to drive demand for Proofpoint's full suite of security and compliance solutions.

Answer: developer