Utilize the input text as a context reference, choose the right relationship between green and Tokyo 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.

I mean, people are talking about a lot of different theories, but we have come up with a way of taking green hydrogen and actually converting it to something that can be transported and delivered to a different station in whether it is in Frankfurt or Tokyo or Shanghai.

Answer: headquarters_location