Utilize the input text as a context reference, choose the right relationship between Klaus Kleinfeld and Chief Executive Officer 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.

The largest U.S. aluminum producer said it imposed a global salary and hiring freeze as it seeks to cope with what Chief Executive Officer Klaus Kleinfeld called "extraordinary times."

Answer: position_held