Utilize the input text as a context reference, choose the right relationship between Plug Power and fuel cell from the options. Options: 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.

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.

Answer: product_or_material_produced