What is the relationship between 'Plug Power' and 'fuel cell' in the context of the input sentence.
Options: product/material produced, legal form, member of, platform

Leading fuel cell developer, Plug Power Inc. PLUG enjoyed an upswing of as much as 14.8% on Monday to close at $2.17 per share on conjectures that big orders could be on the way from Atlanta, GA-based home improvement retailer The Home Depot, Inc. HD.
product/material produced