What is the relationship between 'Stratasys' and '3D printing' in the context of the input sentence.
Options: founded by, product/material produced, stock exchange, owner of

Stratasys subsidiaries include MakerBot and Solidscape and the Stratasys ecosystem includes 3D printers producing prototypes and parts; a wide range of 3D printing materials; parts on-demand via Stratasys Direct Manufacturing; strategic consulting and professional services; and Thingiverse/GrabCAD communities with 5+ million free design components, printable files.
product/material produced