Refer to the input text as context and select the correct relationship between 'Windows 10' and 'Microsoft' from the available options.
Options: member of, developer, product/material produced, headquarters location

Here are six important things you should know about Microsoft Windows 10... Microsoft announced that Windows 10 will be free for customers running Windows 7, Windows 8.1, and Windows Phone 8.1 if they upgrade in the first year after launch.
developer