Utilize the input text as a context reference, choose the right relationship between 'Stratasys' and '3D printing' from the options.
Options: distributed by, product/material produced, member of, distribution format

Troy Jensen at Piper Jaffray said that the 3D printing industry is "starting to show signs of reacceleration," with the outlook for Stratasys being more positive than that for 3D Systems.
product/material produced